Quality Assurance in Analytical Chemistry: Training and Teaching - Second edition

Quality Assurance in Analytical Chemistry Bernd W. Wenclawiak • Michael Koch Evsevios Hadjicostas Editors Quality As...

Author: Bernd W. Wenclawiak | Michael Koch | Evsevios Hadjicostas

410 downloads 2412 Views 4MB Size Report

This content was uploaded by our users and we assume good faith they have the permission to share this book. If you own the copyright to this book and it is wrongfully on our website, we offer a simple DMCA procedure to remove your content from our site. Start by pressing the button below!
Report copyright / DMCA form

DOWNLOAD PDF

Quality Assurance in Analytical Chemistry

Bernd W. Wenclawiak • Michael Koch Evsevios Hadjicostas Editors

Quality Assurance in Analytical Chemistry Training and Teaching Second Edition

Editors Prof. Dr. Bernd W. Wenclawiak Universität Siegen FB 8 Chemie Inst. Analytische Chemie 1 Adolf-Reichwein-Str. 2 57068 Siegen Germany [email protected]

Dr. Michael Koch Universität Stuttgart Inst. Siedlungswasserbau Wassergüte-und Abfallwirtschaft Abt. Chemie Bandtäle 1 70569 Stuttgart Germany [email protected]

Dr. Evsevios Hadjicostas Quintessence Enterprises Ltd. Kennedy Business Center Office 208 12-14 Kennedy Avenue 1087 Nicosia Cyprus [email protected]

The terms and definition taken from ISO 9004:2000, Fig. 1, Quality management systemsguidelines for performance improvements, are reproduced with the permission of the International Organization for Standardization, ISO. This standard can be obtained from any ISO member and from the Web site of the ISO Cental Secretariat with the following address: www.iso.org. Copyright remains with ISO. Additional material to this book can be downloaded from http://extras.springer.com

e-ISBN 978-3-642-13609-2 ISBN 978-3-642-13608-5 DOI 10.1007/978-3-642-13609-2 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2010932320 © Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: WMXDesign GmbH, Heidelberg, Germany Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Foreword to the Second Edition The first edition of this book came out 2004 and it has been proven very popular with over 1,000 copies sold. With the rapid changes in this field and the publication of the new standard in terminology ISO Guide 99 (VIM3) a decision was taken to make an update. All chapters have been revised in order to follow the terminology in VIM3. The main work of the update was performed by Michael Koch. In this edition also two contributors have taken part in the work, Michael Gluschke and Bertil Magnusson. The number of slides has increased from 756 to slightly more than 800 and the slides in the accompanied electronic material are now available in both English and German. A programme for control charts was added to the electronic material. Important chapter updates: •

• •

Measurement uncertainty: Since 2004 there has been considerable development in approaches to estimation of uncertainty and this chapter has been considerable revised and expanded in order to take into account new guidelines. Main difference is that several ways of estimating measurement uncertainty are know full acceptable and the analyst is free to choose approach dependent on scope and data availability. Calibration: Considerable feedback showed that there was room for improvement. The chapter has been fully revised based on this feedback from readers which we here would like to acknowledge. Validation of analytical methods: We all know that validation is to assess fitness for intended purpose. It was therefore logical to combine the separate chapters on Fit for purpose and Validation in the first edition into one chapter. Bertil Magnusson

Foreword to the First Edition The application of Quality Assurance (QA) techniques has led to major improvements in the quality of many products and services. Fortunately these techniques have been well documented in the form of guides and standards and nowhere more so than in the area of measurement and testing, particularly chemical analysis. Training of analysts and potential analysts in quality assurance techniques is a major task for universities and industrial and government laboratories. Re-training is also necessary since the quest for improvements in quality seems to be never ending. The purpose of this book is to provide training material in the convenient form of PowerPoint slides with notes giving further details on the contents of the slides. Experts in the relevant topic, who have direct experience of lecturing on or utilising its contents, have written each chapter. Almost every aspect of QA is covered from basic fundamentals such as statistics, uncertainty and traceability, which are applicable to all types of measurement, through specific guidance on method validation, use of reference materials and control charts. These are all set in the context of total quality management, certification and accreditation. Each chapter is intended to be self-contained and inevitably this leads to some duplication and cross-references are given if there is more detailed treatment in other chapters. The accompanying CD contains over 700 PowerPoint slides, which can be used for presentations without any or with little modification and there are extensive lists of references to the guides and standards that can be used to amplify the notes given with each slide. The use of the material in this book should considerably reduce the time and effort needed to prepare presentations and training material. Alex Williams

Preface and Introduction The importance of quality assurance of chemical measurements not only for global trade but also for a global society has been characterized in a statement by Paul de Bièvre, one of the forerunners concerned about analytical results and their use in widespread applications: Chemical measurements are playing a rapidly expanding role in modern society and increasingly form the basis of important decisions. Acceptability of food is dependent on a knowledge of its ingredients e.g. how pure is the drinking water or is there acrylamide in french fries or other fried food preparations, how much vitamin C, or ß-carotene, or proline is there in juices, what preservatives are there in bread, sausages or other food preparations? Alloys have to meet certain specifications to be used in tools, machinery or instruments. The price of platinum ores or used catalytic converters from cars depends on the platinum content. There are many more examples. This shows the importance of correct analytical results. The question is: Why are correct analytical results so important today? The following statements help to understand why: For correct decisions one needs regulations (e.g. ISO standards). • • • •

Regulations mean limits have to be set and controlled. Regulations have an impact on commercial, legal or environmental decisions. Quality of traded goods depends on measurements that in turn can be trusted. (Measurements have to be of good quality and reliable.) Good measurements require controllable and internationally accepted and agreed procedures.

High quality measurements require qualified specialists. A specialist needs not necessarily a university degree in chemistry. Anyone who is well trained and familiar with the field can become a specialist. However specialists need re-training and their knowledge updating on a regular basis. To help with understanding the different topics involved and to provide a sound basis for quality assurance in an analytical laboratory and also to provide material for teaching and (self) training we have compiled a series of chapters by different authors covering the most important topics. The transparencies are intended for teaching purposes but might also be suitable to give an overview of the subject. We hope that our work will reduce the burden of finding all this information yourselves. All information in this edition has been updated or corrected to the best of our

X

Preface and Introduction

knowledge. This material provided has been collected from different sources. One important source is the material available from EURACHEM. Eurachem is a network of organisations in Europe having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices. It provides a forum for the discussion of common problems and for developing an informed and considered approach to both technical and policy issues. It provides a focus for analytical chemistry and quality related issues in Europe. You can find more information about EURACHEM on the internet via “Eurachem –A Focus for Analytical Chemistry in Europe” (http://www.eurachem.org). In particular the site Guides and Documents contains a number of different guides, which might help you to set up a quality system in your laboratory. The importance of quality assurance in analytical chemistry can best be described by the triangles depicted in Figs. 1 and 2. Quality is checked by testing and testing guaranties good quality. Both contribute to progress in QA (product control and quality) and thus to establishing a market share. Market success depends on quality, price, and flexibility. All three of them are interconnected. Before you can analyse anything the sample must be taken by someone. This must be of major concern to any analytical chemist. There is no accurate analysis without proper sampling. For correct sampling you need a clear problem definition. There is no correct sampling without a clear problem definition Because the sampling error is usually the biggest error in the whole analysis, care must be taken to consider all aspects from sampling. Measurement uncertainties arising from the process of sampling and the physical preparation of the sample can be estimated.

Quality Progress Testing Fig. 1 Factors that influence the market

Market


XI

Price

Market Flexibility

Quality

Fig. 2 Factors that influence market success

Sampling is just the beginning of the analytical process. On the way from sampling to the test report a lot of different requirements for high quality measurements have to be considered. There are external quality assurance requirements on the quality management system (e.g. accreditation, certification, GLP), internal quality assurance tools (e.g. method validation, the use of certified reference material, control charts) and external quality assurance measures (e.g. interlaboratory tests). The aim of this book is to deal with all of these topics in a form that can easily be used for self-training and also for teaching in educational institutions and for in-house training. Teachers that intend to use this material to introduce the presented topics to their students or an audience are advised to study and digest the material before they use it in their presentations. The slides could then be customized to meet the needs of the teacher. It is important to note that the material provides the basis for presentations by third parties rather than exhaustive and fully comprehensive material. The intention is to give an overview of all topics relevant for quality assurance in chemical measurement. For details on single topics we refer the reader to the relevant specialized literature. We have added some recent references for further studies and information at the end of each chapter. The editors hope that they can contribute to a better understanding of quality assurance tools and the quality assurance system as a whole. They wish to promote the use of these tools in order to achieve world wide comparable measurement results.

XII


The editors wish to thank Mr. Enders, Mr. Pauly and Springer–Verlag for their support throughout the whole project. We would also like to thank all contributors for their work. Without their help this task would not have been possible. Siegen, Germany Stuttgart, Germany Nicosia, Cyprus Summer, 2010

B. Wenclawiak M. Koch E. Hadjicostas

List of Contributors Michael Gluschke Dottikon Exclusive Synthesis AG Quality management P.O. Box 5605 Dottikon Switzerland [email protected] Evsevios Hadjicostas Quintessence Enterprises Ltd Kennedy Business Center Office 208 12-14 Kennedy Avenue 1087 Nicosia Cyprus [email protected]

Bertil Magnusson SP Technical Research Institute of Sweden Chemistry and Materials Technology P.O. Box 857 50115Borås Sweden [email protected] Ioannis Papadakis International Quality Certification Megistis 25 GR-17455, Alimos, Athens Greece [email protected]

Rüdiger Kaus Laboratory of Water Chemistry and Water Technology University of Applied Science. Niederrhein Adlerstr. 32 47798 Krefeld Germany [email protected]

Kyriacos C. Tsimillis The Cyprus Organization for the Promotion of Quality – The Cyprus Accreditation Body c/o Ministry of Commerce, Industry and Tourism 13-15 Andreas Araouzos str. CY-1421, Nicosia, Cyprus [email protected]

Michael Koch Institute for Sanitary Engineering University of Stuttgart Bandtäle 2 70569 Stuttgart Germany [email protected]

Bernd Wenclawiak Inst. Analytische Chemie 1 Universität Siegen FB 8 Chemie Adolf-Reichwein-Str. 2 57078 Siegen Germany [email protected]

Contents Foreword to the Second Edition ............................................................................. V Foreword to the First Edition............................................................................... VII Preface and Introduction........................................................................................IX List of Contributors............................................................................................. XIII Contents ............................................................................................................... XV Important Information for Readers and Users of the Electronic Material.........XVII Glossary of Analytical Chemistry Terms (GAT) .................................................... 1 B. Wenclawiak Accreditation – ISO/IEC 17025............................................................................. 19 R. Kaus ISO 9000 Quality Management System ................................................................ 45 E. Hadjicostas Accreditation or Certification for Laboratories? ................................................... 73 K. Tsimillis Good Laboratory Practice...................................................................................... 95 E. Hadjicostas Total Quality Management and Cost of Quality ................................................. 113 E. Hadjicostas Quality Manual .................................................................................................... 143 M. Koch Basic Statistics ..................................................................................................... 161 M. Koch Calibration ........................................................................................................... 183 M. Koch Metrology in Chemistry and Traceability of Analytical Measurement Results.................................................................................................................. 201 I. Papadakis, B. Magnusson Validation of Analytical Methods – to be Fit for the Purpose............................. 215 B. Wenclawiak, E. Hadjicostas

XVI

Contents

Measurement Uncertainty.................................................................................... 247 M. Koch Control Charts...................................................................................................... 273 M. Koch, M. Gluschke (Certified) Reference Materials ........................................................................... 289 I. Papadakis Interlaboratory Tests ............................................................................................ 303 M. Koch Index .................................................................................................................... 327

Important Information for Readers and Users of the Electronic Material Viewing and Printing the Transparencies The transparencies are available from the Springer Webserver under www.extras. springer.com/2010/978-3-642-13608-5. You will find four zipped files there: − − − −

Transparencies_English.zip Transparencies_German.zip ExcelKontrol_2.1_English.zip ExcelKontrol_2.1_German.zip

The first two contain all the transparencies in English and German language respectively and the latter two the control charts programme ExcelKontrol 2.1. To view the transparencies or use the programme contained in the zipped files, you will have to enter the password that you find printed at the end of Chap. 15. We strongly recommend that you download the zipped files to your own computer. The transparencies are edited in Microsoft® PowerPoint® 2000. If you do not have Microsoft® PowerPoint® 2000 or a later version on your PC you can look at and print the transparencies with Microsoft® PowerPoint Viewer for PowerPoint, which is available free of charge on the Microsoft homepages. Important Notice After entering the password that you find printed at the end of Chap. 15, you may access the documents containing the transparencies via opening one of the files INDEX_DE.PPT or INDEX_EN.PPT in the respective folder and clicking on the hyperlinks, provided that you have extracted the zipped files completely on your own computer. Alternatively, you may click on the respective file names (*.ppt). When printing the overheads, please remember to set your printer to the right settings, regarding e.g. the medium of output (paper, overheads), colour, size. If necessary, please consult your PowerPoint® and/or printer handbook.

System Requirements For use with PowerPoint® (recommended) the system requirements are described in the respective software manual.

XVIII

Important Information for Readers and Users of the Electronic Material

EXCEL®-Files The software EXCELKONTROL 2.1 is an EXCEL®-programme for control charts, for which Microsoft EXCEL 2000® (or later) is required. Copyright and License 1. The transparencies in the book are protected by copyright. Any rights in them lie exclusively with Springer-Verlag, for EXCELKONROL the copyright is with the authors Dr. Michael Gluschke and Dr. Michael Koch. 2. The user may use the transparencies, print-outs thereof and multiple copies of the print-outs in classrooms and lecture halls. All copies most show the copyright notice of Springer-Verlag. 3. The user is entitled to use the data in the way described in section 2. Any other ways or possibilities of using the data are inadmissible, in particular any translation, reproduction, decompilation, transformation in a machinereadable language and public communication; this applies to all data as a whole and to any of their parts. Liabilities of Springer-Verlag 1. Springer-Verlag will only be liable for damages, whatever the legal ground, in case of intent or gross negligence and with respect to warranted characteristics. A warranty of specific characteristics is given only in individual cases to a specific user and requires an explicit written representation. Liability under the product liability act is not affected hereby. Springer-Verlag may always claim a contributory fault on the part of the user. 2. The originator or manufacturer named on the product will only be liable to the user, whatever the legal ground, in case of intent or gross negligence. ADDITIONAL CONDITIONS FOR USERS OUTSIDE THE EUROPEAN COMMUNITY: SPRINGER-VERLAG WILL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING ANY LOST PROFITS, LOST SAVINGS, OR OTHER INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING FROM THE USE OF, OR INABILITY TO USE, THE ACCOMPANYING TRANSPARENCIES AND SOFTWARE, EVEN IF SPRINGER-VERLAG HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

1

Glossary of Analytical Chemistry Terms (GAT)

Bernd Wenclawiak Why is it so important to have a glossary of analytical terms? Because there are so many different acronyms, abbreviations, and incorrectly used ‘terms’, that even specialists sometimes have problems in understanding each other. A glossary is like a dictionary with the terms being the words in the vocabulary. Unfortunately not all words are found in one source. This chapter is a compilation of the most used terms. Slide 1 Do you know all those terms on slide 9? Test yourself before you read the definitions given to you here in this chapter (and also in some of the other chapters). It is important, that each term at any time has the same meaning for every user.

Glossary Remark: teaching and learning terms is boring, but necessary! Why is it necessary to know the meaning of a term? Because a lot of expressions are not common in everyday life or might be interpreted differently In scientific and technical work it is necessary that all people use the same “language” 1

W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms

Slide 2 Here are some of the organisations and sources, which provide definitions on terms. Because many of them are often only referred to by their abbreviation, their full title is given here. IUPAC - International Union of Pure and Applied Chemistry (www.iupac.org) ISO - International Organization for Standardization (www.iso.ch) IEC - International Electrotechnical Commission (www.iec.ch)

In: W enclawiak, Koch, Hadj icostas (eds.)

© Springer-Verlag, Berlin Heidelberg 2010 Quality Assurance in Analytical Chemistry – Training and Teaching (2nd ed.)

Glossary Who defines a term? IUPAC Orange Book In chemistry there is IUPAC IUPAC coordinates the international work of harmonization In the field of metrology (science of measurement) many different organizations work together: ISO, IEC , BIPM, OIML, IUPAC, IUPAP, IFCC They jointly published the VIM 2

W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)


B.W. Wenclawiak et al. (eds.), Quality Assurance in Analytical Chemistry: Training and Teaching, DOI 10.1007/978-3-642-13609-2_1, © Springer-Verlag Berlin Heidelberg 2010

1

2

Quality Assurance in Analytical Chemistry – Training and Teaching

BIPM - Bureau International des Poids et Measures (www.bipm.org) OIML - International Organization of Legal Metrology (www.oiml.org) IUPAP - International Union of Pure and Applied Physics (www.iupap.org) IFCC - International Federation of Clinical Chemistry (www.ifcc.org/ifcc.asp) VIM - International Vocabulary of Metrology - Basic and General Concepts and associated Terms Slide 3 In the sources mentioned in this slide you will find more and in some cases complete information on certain terms and definitions. Many of the terms and definitions given in this chapter are taken from these sources.

Glossary - Vocabularies A Vocabulary contains general terms and definitions International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM, 3rd edition, ISO/IE CGuide 99:2007, www.bipm.org) International Vocabulary of Terms in Legal Metrology (VIML) Guide to the Expression of Uncertainty in Measurement (GUM, ISO/IE C-Guide 98:2008, www.bipm. org) ISO 3534-1:2006 “Statistics - Vocabulary and symbols Part 1: General statistical terms and terms used in probability” ISO 3534-2:2006 “Statistics - Vocabulary and symbols - Part 2: Applied statistics ” ISO 3534-3:1999 “Statistics - Vocabulary and symbols Part 3: Design of experiments ” W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms

Slide 4


Guides provide recommendations, which are published by various Glossary organisations. The bibliography comprises four Industrialisation lead to mass producdifferent types of documents: tion with the characteristic feature of Guides the division of the work process into Standards Books smaller individual steps and the Articles (in scientific journals) simplest hand movements, which each worker repeated incessantly. Different parts only fit together if they are made according to a standard. For example the inch is used as the unit for HPLC parts almost everywhere in the world, while screws on the European continent have metric sizes and in the US the inch size is still common. W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

3


© Springer-Verlag, Berlin Heidelberg 2010

Quality Assurance in Analytical Chemistry – Training and Teaching (2nd ed.)

4

1


3

Slide 5 ISO (International Organization of Glossary - Standardization Standardization) was founded in Organizations Geneva in 1947 International: ISO www.iso.org EN is European Norm European: EN www.cen.eu DIN (Deutsches Institut für Normung) German: DIN www.din.de is an Institute in Germany, which Great Britain: BSI www.bsigroup.com United States: ASTM www.astm.org provides standardized industrial You find a list of more countries at production/handling norms www.iso.org/iso/about/iso_members.htm BS or BSI (British Standards Institution) is British Standards, produced by the BSI ASTM (formerly American Society for Testing and Materials) International is a global forum for the development of consensus standards organized in 1898, ASTM International is one of the largest voluntary standards developing organizations in the world. More than 12,000 ASTM standards can be found in the 80+-volume Annual Book of ASTM Standards. W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

5



Slide 6 The system of units used worldwide today is the International System of Glossary – SI System Units, in French, Système Inter The International System of Units (SI) differentiates two classes of units: national d'Unités (SI). The Bureau Base Units and Derived Units. The seven base units are: International des Poids et Mesures Unit Quantity Symbol metre length m (BIPM) adopted the SI system at its kilogram mass kg second time s 11th General Conference on Weights ampere electric current A kelvin thermodynamic temperature K and Measures (Conférence Générale mole amount of substance mol Candela luminous intensity cd des Poids et Mesures –CGPM-) in 1960. The mole was adopted as the seventh SI base unit in 1971. An important factor of the SI system of units is coherence, by which is meant that derived units are defined by the multiplication and/or division of the base units, without the need for any numerical factors. 6




4


Slide 7 Very important sources of information Glossary - Important Organisations today are the websites on the Internet. European EURACHEM (Co-operation for EURACHEM - Co-operation for Analytical Chemistry in Europe Analytical Chemistry in Europe) EUROLAB - Organization for Testing in Europe EA - European Co-Operation for Accredit ation http://www.eurachem.org EUROME T - A European Collaboration in Measurement Standards EUROLAB (Organization for Testing IRMM Institute for Reference Materials and Measurements International in Europe) http://www.eurolab.org CITAC - Co-Operation on International Traceability in Analytical Chemistry EA (European Co-operation for NIS T – (US ) National Institute of Standards and Technology ILA C - the International Laboratory Accreditation Accreditation) http://www.europeanCooperation APLAC Asia Pacific Laboratory Accreditation Cooperation accreditation.org/ IRMM (Institute for Reference Materials and Measurements; European Commission Joint Research Centre) http://irmm.jrc.ec.europa.eu. CITAC Cooperation on International Traceability in Analytical Chemistry http://www.citac.cc. NIST (agency of the US Commerce Department‘s Technology Administration) http://www.nist.gov. ILAC (International Laboratory Accreditation Cooperation) http://www.ilac.org. APLAC (Asia Pacific Laboratory Accreditation Cooperation) http://www.aplac.org/ W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

7



Slide 8 The terms presented here are separated into different fields for better clarity and to enable comparison. So you might want to follow up only those, of the six specific headings given here, that you need.

Glossary - Terms Related to:

General Statistics Validation Measurement Error Uncertainty 8



1


5

Slide 9 This is the compilation of those terms, which can be related to topic “General”. In the following slides the definitions will be given. In the upper left corner of the following slides you find the allocation to the main area the term is allocated to.

General Terms

Glossary of General Terms

Accreditation Accuracy Accuracy of measurement Accuracy of a Measuring Instrument Audit Bias Certification Fitness for Purpos e Influence quantity Precision Intermediate Precision

Quality

Quality Assurance Quality Control Internal Quality Control Standard Trueness Value

Accepted Reference Value True Value Conventional True Value 9


Slide 10



The conformity assessment body could General Terms be a laboratory, the third-party could Accreditation be the accreditor coming to your labo Third-party attestation related to a ratory to inspect, whether the required conformity assessment body conveying documentation, manuals, procedures, formal demonstration of its competence to carry out specific conformity or personnel are appropriate to assessment tasks perform the specific conformity [ISO/IEC 17000:2004] assessment task e.g. determine PAHs (See also chapter 2) by HPLC. If the laboratory (the conformity assessment body) and the personnel can do the job then accreditation might be granted. Being accredited can be of competitive advantage for laboratories. Sometimes contractors require the (analytical) work to be carried out in an accredited laboratory. Accreditation gives confidence to the customer that the laboratory will fulfil the requirements that are necessary for the work to be done competently. You find more about accreditation in chapter 2 of this book.

10




Slide 11 Accuracy is the closeness of a result to a true value. This again is the combination of trueness and precision and defines measurement uncertainty. (See also chapter 12). Accuracy is greater when the quantity value is closer to the true value

General Terms

Accuracy Closeness of agreement between a measured quantity value and a true quantity value of a measurand [VIM] Accuracy is a measure which combines precision and trueness (i.e. the effects of random and systematic factors) Suppose the results produced by the application of a met hod show zero or very low bias (i.e. are "true"), their accuracy becomes equivalent to their precision. If the precision is poor, any particular result will be inaccurate If a method shows a high bias, even results with a high precision are inaccurat e The concept ‘measurement accuracy’ is not a quantity and is not given a numerical quantity value [VIM]. 11



6


Slide 12 For example: For contract work an auditor comes to the laboratory and checks whether the staff perform the task according to (agreed) standards, utilising appropriate laboratory equipment correctly. This is also called assessment or external audit. Internal auditors can be colleagues (from a different laboratory in the same company or a different working area). Reviews are usually carried out by upper level managers. See also chapter 2.

General Terms

Audit Systematic, independent, documented process for obtaining records, statements of fact or other relevant information and assessing them objectively to determine the extent to which specified requirements (need or expectation that is stated) are fulfilled [ISO 17000] Whilst “audit” applies to management systems, “assessment” applies to conformity assessment bodies as well as more generally. 12



Slide 13 Bias is the total systematic error (there may be more than one component contributing to total systematic error). It is the (positive or negative) difference (Δ) of the population mean (μ, the limiting value of the arithmetic mean for n→∞) from the (known or assumed) true value (τ). Δ = μ - τ. Therefore bias is the lack of trueness.

General Terms

Bias (Δ) The difference between the population mean (μ) and the ‘true‘ value (τ) i.e., Δ = μ - τ (signed quantity) [IUPAC Orange book]

Since the ‘true’ value is principally unknown, a conventional true value is used to estimate the bias Comment: Bias is the total systematic error 13



Slide 14 The confirmation of certain characteristics of a material, person, or organisation is called certification. This confirmation is often provided by an external audit or assessment (u.s.). Quality management systems are often certified for conformation with ISO 9000. Probably the most common term with respect to our topic here is ‘certified reference material’ (CRM). A driver’s licence is a certificate,

General Terms

Certification Third-party attestation (issue of a statement) related to products, processes, systems or persons [ISO 17000] Certification of a management system is sometimes also called registration. Certification is applicable to all objects of conformity assessment except for conformity assessment bodies themselves, to which accreditation is applicable. 14



1


7

documenting the competence of the driver to participate in car traffic, usually obtained after an examination. (See also chapters 10 and 14) Slide 15 Fitness for purpose is the ultimate goal of the person doing the job in the laboratory. It is also a requirement of the instrument used to perform an analysis and of the method chosen to get a correct result. Check in chapter 11 on this topic for further information.

General Terms

Fitness for Purpose Degree to which data produced by a measurement process enables a user to make technically and administratively correct decisions for a stated purpose. [IUPAC Orange Book]

15



Slide 16 Examples of influence quantities are: Temperature of a micrometer used to measure length; Frequency in the measurement of an alternating electric potential difference; Bilirubin concentration in the measurement of haemoglobin concentration in human blood plasma.

General Terms

Influence Quantity A quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and the measurement result [VIM] 16



Slide 17 If a number of results are close to each other we say that we have a good precision. Precision means proximity of test results. Keep in mind that they could be far away from the true value. In this case precision is still very good but the values are wrong on average. So the accuracy is pretty bad.

General Terms

Precision Closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions [VIM]

The precision of a set of results of measurements can be quantified e.g. as a standard deviation 17



8


Slides 18-20 The quality of a product or a service is the degree to which a set of inherent characteristics fulfils requirements. For products this means e.g. properly made, defect free, made to agreed size. For service this means e.g. fast, reliable, and correct. Quality can be good or poor. The quality of data should always be as good as possible, but there is no need that they are better than required. The word “quality” is derived from the Latin “qualitas”, which means, incidentally, only the “nature” and “inherent characteristics” of a thing. In everyday speech we understand by this term above all two aspects, faultlessness (“a product with no defects” is of high quality) and performance capability or serviceableness (“a product that comes up to all our requirements and can be easily handled is qualitatively perfect”). See also chapter 6.

General Terms

Quality Degree to which a set of inherent characteristics fulfils requirements [ISO 9000]

A very important remark: “No data is better than poor data”

18



General Terms

Quality - What does that Mean? “Quality means that the customer comes back, ...

19



General Terms

Quality - What does that Mean? ... and not the product”.

20



1


9

Slide 21 Quality assurance is the main goal of this book. The authors want to provide the reader or user with a product or service (this book) that can satisfy the needs and which is hopefully fit for purpose.

General Terms

Quality Assurance Part of quality management focused on providing confidence that quality requirements will be fulfilled [ISO 9000]

All the planned and systematic activities implemented within the quality system, and demonstrated as needed, to provide adequate confidence that an entity will fulfil requirements for quality [IUPAC Orange Book]

21


Slide 22



General Terms Everybody has heard or used that term. For example chromatography Quality Control column manufacturers assure a Part of quality management certain specification e.g. the minimum (coordinated activities to direct and plate number or separation efficiency control an organization with regard to quality) focused on fulfilling quality for defined analytes. In our context requirements that means: make sure that the instru[ISO 9000] ment and our method works reliably within certain limits. To be certain that they really do, you should check this e.g. with a reference material (in liquid chromatography for example with an Engelhardt test solution). If there are deviations from previous performed tests, take action to correct this. In Analytical Chemistry control charts, analysis of certified reference materials and interlaboratory comparisons are very important quality control tools (see chapters 13-15). W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

22



Slide 23 You could decide to use control charts and to analyse certified reference materials (see chapter 13 and 14). Control charts are a simple, but effective tool for internal quality control. “Internal quality control is one of a number of concerted measures that analytical chemists can take to ensure that the data produced in the laboratory are fit for their intended purpose.” (Cited from IUPAC Orange Book).

General Terms

Internal Quality Control IQC Set of procedures undertaken by laboratory staff for the continuous monitoring of operations and the results of measurements in order to decide whether results are reliable enough to be released [for complete definition see IUPAC Orange Book]

23



10


Slide 24 In this book, standard is used only in the sense of written standard and the term measurement standard or etalon (in French “étalon”)(see slide 36) is used to describe chemical or physical standards used for calibration purposes such as: chemicals of established purity and their corresponding solutions of known concentration, UV filter, weights, etc. They are also called: reference materials.

General Terms

Standard The term standard has two different meanings: A written standard is used for widely adopted procedures, specifications, technical recommendations etc. And also as chemical or physical measurement standard, which is used for calibration purposes

Standard is used here only in the sense of written standard 24



Slide 25 Trueness is a property related to systematic errors. It is the closeness of agreement between the average value obtained from a large set of test results and an accepted reference value. It can be checked with reference materials or in interlaboratory comparisons.

General Terms

Trueness Closeness of agreement between the average of an infinite number of replicate measured quantity values and a reference quantity value [V IM] A reference quantity value is a value with little (or ideally no) systematical error Perfect trueness cannot be achieved, so trueness in its analytical meaning is always trueness within certain limits These limits may be narrow at a high concentration level and wide at the trace level

Note the differenc e between accuracy and trueness. The lack of trueness is called bias

25



Slide 26 True value (of a quantity) is the ultimate goal when analyzing samples. However no measurement is perfect and thus true values are indeterminate by nature.

General Terms

True value (τ) Quantity value consistent with the definition of a quantity [VIM] The true value is a theoretical concept and, in general, cannot be known exactly It is a value that would be obtained by a perfect measurement True values are by nature indeterminate 26



1


11

Slide 27 Values stated on reference materials are conventional true values. The results are usually obtained by independent methods in different expert laboratories. The conventional true value should be close enough to the true value. In proficiency tests the mean of the participants results is often used as a conventional true value.

General Terms

Conventional True Value Value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose [IUPAC Orange Book] A result obtained by using several independent methods in several expert laboratories on one measurand is regarded as conventional true value of a quantity even if it is not the "true" value

A conventional true value is in general, regarded as sufficiently close to the true value 27



Slide 28 This is a selection of terms related to statistics. You will find more detailed descriptions in chapter 8 – “Basic Statistics”.

Glossary on Statistical Terms

Arithmetic mean Distribution functions Normal distribution Rectangular distribution Triangular distribution Poisson distribution Binomial distribution Estimate

Probabilty Standard Deviation Sample Standard Deviation Standard deviation of the mean Relative Standard Deviation (RSD)

28


Slide 29


Distributions are derived from data to give a mathematical description or a model for the data. You will find much more detailed information on this topic in textbooks on statistics.

Statistical Terms


Distribution Functions Normal distribution continous distribution Rectangular distribution Triangular distribution Poisson distribution Binomial distribution

discrete function discrete function

29



12


Slide 30 These are the terms that are associated with validation. Many of these terms are explained in detail in the chapters 11- “Fit for Purpose and Validation of Analytical Methods”, and 8 - “Basic Statistics”. So please check there. A few examples (of the more often used terms) are presented on the next slide.

Glossary on Validation Terms

Calibration Curve Linear least squares calibration Cross Reactiv ity Discrimination

Population Mean Limit of Detection Minimum Detectable Concentration Limit of Decision Limit of Determination Limit of Quantitation Linearity Proficiency Testing Range - Measuring and working Recovery Reference Material

Discrimination Threshold

Certif ied Ref erence Material

Repeatability Repeatability of Results of Measurements Repeatability of a Measuring Instrument Repeatability Standard Deviation Repeatability Limit r Reproducibility Reproducibility Standard Deviation Reproducibility Limit R Ruggedness Test Selectivity Selectivity in Analysis Sensitivity Validation

Verif ication

Method Valid ation

30


Slide 31



Validation Terms The ISO 9000:2005 states that validation is the confirmation by examinaSelected Validation Terms tion and provision of objective Validation Population Mean evidence that the particular require Method Validation Limit of Detection ments for a specified intended use are Instrument Validation Minimum Detectable Verification Concentration fulfilled. Proficiency Testing Limit of Method Validation is the process of Quantification establishing the performance characteristics and limitations of a method and of verifying that a method is fit for purpose, i.e. for use for solving a particular analytical problem. Instrument validation should show that an instrument is able to perform according to its design specification. This can be done for example by means of calibration or performance checks [Eurachem Guide Fit for Purpose] Verification is confirmation by examination and provision of objective evidence that specified requirements have been fulfilled. ISO 9000:2005 Proficiency testing is a periodic assessment of the performance of individual laboratories and groups of laboratories that is achieved by the distribution by an independent testing body of typical materials for unsupervised analysis by the participants. [IUPAC Orange Book] Population Mean (μ) The asymptotic value of the distribution that characterizes the measured quantity; the value that is approached as the number of observations approaches infinity. Modern statistical terminology labels this quantity the expectation or expected value, E (x). [IUPAC Orange Book] Limit of detection (LoD) is the lowest concentration that can be detected with specified confidence for a specific substance. The Minimum Detectable Concentration (MDC) is the detection limit expressed as a concentration. 31




1


13

Limit of Quantification, (LoQ), sometimes also called limit of quantitation or limit of determination, is the minimum content that can be quantified with a certain confidence. Values below LoQ are reported as less than. Slide 32 Validation Terms

Calibration Curve Graphical representation of the calibration function relating the expected value of the observed signal or response variable E(y) to the analyte amount x 5,00E+06 4,50E+06

[IUPAC Orange Book]

4,00E+06 3,50E+06 Peakfläche (Counts)

Calibration Curve is the graphical plot of the calibration function. The plot relates the signal to the analyte amount or concentration. Linear least squares calibration is a calibration obtained using the method of minimizing the least squares. Sometimes calibration curves of higher order are used.

y = 10798x - 34511 R2 = 0,9998

3,00E+06 2,50E+06 2,00E+06 1,50E+06 1,00E+06 5,00E+05 0,00E+00 0

50

100

150

200

250

300

350

400

450

- 1

µg L


32


Slide 33 See chapter 9 – “Calibration and detection limits”

Validation Terms

Linear Least Squares Calibration Calibration with the method of minimizing the least squares

Slide 34

33


The linearity definition is on the slide. As long as the measurement result versus the analyte concentration fits a straight line we call this linearity. In an ideal case linearity could extend over several orders of magnitude. This is, for example, the case for certain elements when determined by ICPOES. In other cases it can be less than one order of magnitude. Linearity over a large concentration can be very time saving, because fewer dilution steps might be necessary (see also chapter 9).


Validation Terms

Linearity The ability of an analytical method to elicit test results that are directly, or by a well defined mathematical transformation, proportional to the concentration of analyte in samples within a given range [AOAC] The Linear Range is by inference the range of analyte concentrations over which the method gives test results proportional to the concentration of the analyte 34



14


Slide 35 Measurand is the quantity we want to Glossary on Measurement measure. Terms Measurement is the process of Measurand experimentally obtaining one or more Measurement quantity values that can reasonably be Measurement Procedure attributed to a quantity Measurement Method Measurement procedure is the detailed Measurement Result description of a measurement. An operator should be able to measure a measurand following the description. Measurement method is the generic description of a logical organization of operations used in a measurement Measurement result is the information about the magnitude of a quantity, obtained experimentally. The information consists of a set of quantity values being attributed to the measurand together with any other available relevant information. This is usually summarized as a single quantity value and a measurement uncertainty. The single quantity value is an estimate, often an average or the median of the set. It should state the number of repetitions (n) used to obtain the averaged value and if possible it should state the relative standard deviation (RSD). [All definitions from VIM] 35




Slide 36 This slide gives the definition of a measurement standard: You could also use the term reference material. You will find more information on this topic in the chapters 10 and 14. The different definition of a (written) standard is on slide 24.

Measurement Terms

Measurement Standard Realization of the definition of a given quantity, with stated quantity value and associated measurement uncertainty, used as a reference [VIM]

36



1


15

Slide 37 Error of measurement can be due to random and systematic error. Random Error is related to precision (see Slide 17) and Systematic Error to trueness (see Slide 25).

Error Terms

Error of Measurement Random Error Systematic Error False Negatives/Positives

37



Slide 38 Error (of measurement) is the sum of random and systematic errors of one measurement. Since a true value cannot be determined, in practice a reference quantity value is used. Each individual result of a measurement will have its own associated error.

Error Terms

Error (of a Measurement) Measured quantity value minus a reference quantity value [VIM] Error is the sum of random and systematic errors If a measurement is repeated, each individual result will have its own associated error 38


Slide 39



Error Terms IUPAC’s Orange Book states two kinds of errors (really erroneous deciFalse Positives / Negatives sions): the error of the first kind (“type For qualitative methods the false I”, false positive), and the error of the positives/negatives rate may be determined. Data from a confirmatory method comparison second kind (“type II”, false negative. should be provided if such method(s) is The probability of the type I error is applicable to the same matrix(es) and concentration range(s). indicated by α; the probability for the In the absence of a method comparison, populations of negative and positive fortified type II error, by ß. Default values samples must be analysed. recommended by IUPAC for α and ß [Eurachem Fit for Purpose] are 0.05, each. False positives/negatives may be determined as follows: False positive rate (%) = false positives · 100/total known negatives False negative rate (%) = false negatives · 100/total known positives W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

39



16


Slide 40 See also chapter 12 – “Measurement Uncertainty”. Uncertainty is a fundaUncertainty mental property of a result. Standard Uncertainty is the uncer Uncertainty (of Measurement) tainty of a measurement expressed as Standard Uncertainty Combined Standard Uncertainty a standard deviation. Expanded Uncertainty Combined Standard Uncertainty is the Coverage Factor standard uncertainty that is obtained Type A evaluation (of uncertainty) Type B evaluation (of uncertainty) by combining (root of the sum of squares) individual standard measurement uncertainties associated with the input quantities in a measurement model. Expanded Uncertainty is the combined standard uncertainty multiplied with the coverage factor k. Often k is chosen to be 2 or sometimes 3. With k=2 about 95%, and with k=3 about 99% of all likely values are encompassed. Type A evaluation (of uncertainty): Method of evaluation of uncertainty by the statistical analysis of series of observations. Type B evaluation (of uncertainty): Method of evaluation of uncertainty by means other than the statistical analysis of series of observations. [Definitions from VIM] 40




Slide 41 Uncertainty Terms Uncertainty (of Measurement) i.e. Measurement Uncertainty. The slide Measurement Uncertainty contains the (newer) definition in Non-negative parameter characterizing the VIM. In GUM it is defined as: dispersion of the quantity values being attributed to a measurand, based on the information used [VIM] “Parameter associated with the result of Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated a measurement, that characterises the from the statistical distribution of the results of series of measurements and can be characterized by experimental dispersion of the values that could standard deviations The other components, which can also be characterized by reasonably be attributed to the standard deviations, are evaluated from assumed probability distributions based on experience or other information measurand”. The parameter may be, for example, a standard deviation (or a given multiple of it), or the half width of an interval having a stated level of confidence. W enclawiak, B.: Glo ssar y of Analyt ical Chemi str y T erms In: W enclawiak, Koch, Hadj icostas (eds.)

41



1


17

Slide 42 As stated on the slide, traceability should allow to trace the result of a measurement or the value of a standard through an unbroken chain of calibrations to stated references. Traceability is one key issue of ISO 17025. You find more on measurement traceability in chapter 10.

Metrological Traceability Property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty [VIM]

42


Bibliography



AOAC Terms and Definitions http://www.aoac.org/terms.htm ISO (1998) SI-Guide, 32 p., ISBN 92-67-10279-6 ISO 3534-1:2006, Statistics - Vocabulary and symbols - Part 1: General statistical terms and terms used in probability ISO 3534-2:2006, Statistics - Vocabulary and symbols - Part 2: Applied Statistics ISO 3534-3:1999, Statistics - Vocabulary and symbols - Part 3: Design of experiments ISO 9001:2000, Quality management systems – Requirements ISO/IEC Guide 2:2004, Standardisation and related activities - General vocabulary ISO/IEC Guide 98:1995 Guide to the expression of uncertainty in measurement (GUM), also available as JCGM 100:2008 from www.bipm.org ISO/IEC Guide 99:2007 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM), 3rd edition, also available as JCGM 200:2008 from www.bipm.org IUPAC (1997) Gold book - Compendium of Chemical Terminology, http://goldbook.iupac.org/index.html IUPAC (1998) Orange book- “Compendium on Analytical Nomenclature”, 3rd edition, http://old.iupac.org/publications/analytical_compendium/ Neidhart B, Albus HE, Fleming J, Tausch C, Wegscheider W(1996-1998) Glossary of analytical terms. Accredit. Qual. Assur.

2

Accreditation – ISO/IEC 17025

Rüdiger Kaus This chapter gives the background on the accreditation of testing and calibration laboratories according to ISO/IEC 17025 and sets out the requirements of this international standard. ISO 15189 describes similar requirements especially tailored for medical laboratories. Because of these similarities ISO 15189 is not separately mentioned throughout this lecture. Slide 1 Chemical measurements are widely used for different purposes, e.g. as a basis for decision. Quite often the consequences of wrong decisions would be very costly. So the quality of chemical measurements is very important. Since customers of chemical laboratories are normally not able to judge the quality of a laboratory, an independent check of a laboratory by a third party is of utmost importance.

The Value of Chemical Measurements Depends much on the level of confidence that can be placed in the results Using quality assurance (QA) principles increases at least the likelihood of measurements being soundly based and fit for its purpose Since a usual customer is not able to judge the suitability of a QA system in a laboratory, a formal recognition by a competent third party increases customer‘s confidence 1

Kaus, R.: Accreditation – ISO/IEC 17025 In: W enclawiak, Koch, Hadj icostas (eds.)


Slide 2 Accreditation is the confirmation of the competence of a testing or calibration laboratory by an independent third party, the accreditation body. Normally laboratories are accredited for their fulfilment of the requirements described in the international standard ISO/IEC 17025.

What is Accreditation ? Third-party attestation related to a conformity assessment body (e.g. a testing laboratory) conveying formal demonstration of its competence to carry out specific conformity assessment tasks (e.g. testing) (ISO/IEC 17000:2004)

2




19

20


Slide 3 The structure of the accreditation bodies in each country may be different Accreditation Body and the procedures for accreditation Usually there are national regulations for one can also vary to some extent. But or several accreditation bodies in each country nevertheless they all have to fulfil the There is cooperation between accreditation requirements of ISO/IEC 17011:2004 bodies in international organisations Europe: European Accreditation Cooperation (EA) “Conformity assessment Asia/Australia: Asian Pacific Laboratory Accreditation Cooperation (APLAC) General requirements for accreditation Worldwide: International Laboratory Accreditation bodies accrediting conformity assessCooperation (ILAC) ment bodies”. To further harmonize these procedures and to guarantee multilateral recognition international organisations have been set up by the accreditation bodies, in Europe the European Co-operation for Accreditation (EA) and worldwide the International Laboratory Accreditation Cooperation (ILAC). Kaus, R.: Accreditation – ISO/IEC 17025


3



Slide 4 This slide shows the members of an International Multilateral agreement between Accreditation bodies worldwide, which ensures the mutual recognition of the accreditation for testing and calibration results in the cooperating countries.

International Multilateral Recognition Agreement (MRA) Accreditation bodies from all over the world signed an International MRA on recognition and acceptance of test and calibration results Africa - Eg ypt, South Africa, Tunisia America - Argentina, Brazil, Canada, Costa Rica, Cuba, Guatemala, Mexico, USA

Asia/Australia - Australia, Hong Kong (China), PR China, India, Indonesia, Israel, Japan, Rep. Korea, Malaysia, New Zealand, Pakistan, Philippines, Singapore, Sri Lanka, Chinese Taipei, Thailand, Unit. Arab. Emirates, Vietnam

Europe - Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Netherlands, Norway, Poland, Portugal, Romania, Russian Fed., Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom 4



Slide 5 These are the elements of an accreditation procedure. The first step for the laboratory is to contact the accreditation body, which in response informs the laboratory about the details of the accreditation procedure. When the contract between the laboratory and the accreditation body is signed, assessors will be nominated. They will carry out technical audits of the application document and on-site laboratory

Accreditation Procedure Application to the accreditation body Contract with the accreditation body Nomination and commissioning of assessors Technical audit of the application documents On-site laboratory assessment If necessary proficiency testing Assessment report Inspection of the report in the related committee Accreditation decision Publication

5



2


21

assessment. In many cases it is necessary for the laboratory to participate successfully in proficiency tests. The assessment report of the assessors will be inspected by the members of a local committee which makes a recommendation to accredit the laboratory (or not). Slide 6 ISO/IEC 17025 is the basic standard that is utilised by testing and calibration laboratories for implementing a quality management system and they are accredited for their implementation of this standard. This standard contains the general requirements for the competence of testing and calibration laboratories. It is one of the most important standards for the worldwide globalization of trade.

ISO/IEC 17025:2005 “General requirements for the competence of testing and calibration laboratories”

6



Slide 7 The standard ISO/IEC 17025 focuses on the technical competence for specific tests and this is attested by the accreditation body.

ISO/IEC 17025:2005 Addresses the technical competence of laboratories to carry out specific tests and is used worldwide by laboratory accreditation bodies as the core requirement for the accreditation of laboratories

7



Slide 8 There is a prescribed form for international standards; this is followed by ISO/IEC 17025, which has the general chapters shown here at the beginning.

Contents of ISO/IEC 17025 - I Foreword Introduction 1 Scope 2 Normative references 3 Terms and definitions

8



22


Slide 9 Chapter 4 describes the management Contents of ISO/IEC 17025 - II requirements. It is divided in 15 sub4 Management requirements 4.1 Organization chapters, which can be separated into 4.2 Management System 4.3 Document control three parts: 4.4 Review of requests, tenders and contracts 4.5 Subcontracting of tests and calibrations Organizational (organization, manage4.6 Purchasing services and supplies 4.7 Service to the customer ment system, document control, 4.8 Complaints 4.9 Control of nonconforming testing and/or calibration work 4.10 Improvement control of records) 4.11 Corrective action 4.12 Preventive action Service to the customer (review of 4.13 Control of records 4.14 Internal audits requests, tenders and contracts, sub4.15 Management reviews contracting of tests and calibrations, purchasing services and supplies, service to the customer, complaints) Control of the activities (control of nonconforming testing and/or calibration work, improvement, corrective action, preventive action, internal audits, management reviews) Kaus, R.: Accreditation – ISO/IEC 17025


Slide 10

9



Contents of ISO/IEC 17025 - III 5 Technical requirements

5.1 General In chapter 5 the technical requirements 5.2 Personnel are described. It is divided in 10 5.3 Accommodation and environmental conditions 5.4 Test and calibration methods and method validation sub-chapters: 5.5 Equipment 5.6 Measurement traceability general (overview), personnel, 5.7 Sampling accommodation and environmental 5.8 Handling of test and calibration items 5.9 Assuring the quality of test and calibration results conditions, test and calibration methods 5.10 Reporting the results and method validation, equipment, measurement traceability, sampling, handling of test and calibration items, assuring the quality of test and calibration results, reporting the results. Kaus, R.: Accreditation – ISO/IEC 17025


Slide 11 Annex A and Annex B are not normative, but only for information. A bibliography is the last part of the standard.

10



Contents of ISO/IEC 17025 - IV Annex A (informative) Nominal cross-references to ISO 9001:2000

Annex B (informative) Guidelines for establishing applications for specific fields

Bibliography 11



2


23

Slide 12 The formal statement of the activities Chapter 1 of ISO/IEC 17025: Scope is known as the “scope”. Laboratories A laboratory may apply quality assurance procedures according to ISO/IEC 17025 to all that wish to be accredited for their (or part) of its operations implementation of ISO/IEC 17025 Where a laboratory claims compliance against or certification or accreditation to a have to apply quality assurance proparticular standard, it is important to be clear to what this compliance, certification or cedures to all or part of its operation. accreditation applies Where a laboratory claims compliance The formal statement of the activities, which have been certified against ISO 9001, or (e.g. GLP) against, or certification accredited against ISO 17025 is known as the “scope” (e.g. ISO 9001) or accreditation (e.g. ISO/IEC 17025) to a particular standard, it is important to be clear to what this compliance, certification or accreditation applies. Kaus, R.: Accreditation – ISO/IEC 17025


12



Slide 13 The activities of the laboratory must be clearly stated. The range of the work covered should be defined in detail, but the laboratory’s operation should not be restricted by this definition. Standards are often accused of hindering the development of methods.

Scope of ISO/IEC 17025 - I Quality management is supported by a clear statement of activities, which ideally should define the range of work covered, without restricting the laboratory's operation

13

Kaus, R.: Accreditation – ISO/IEC 17025

Slide 14



Different quality standards have different rules, but for ISO/IEC 17025, Scope of ISO/IEC 17025 - II which addresses laboratories, the is typically defined in terms of: scope may typically be defined in range of products, materials or sample terms of: types range of products, materials or measurements (or types of measurements) specification or sample types tested or analysed; method/equipment/technique measurements (or types of concentration range and uncertainty measurements) carried out; specification or method, equipment and technique used or concentration range and uncertainty as appropriate. Kaus, R.: Accreditation – ISO/IEC 17025


14



24


Slide 15 In the following slides the management requirements are described. This chapter contains all elements of ISO 9001 which are relevant for testing and calibration laboratories. Therefore it is possible that a laboratory that undertakes the accreditation procedure can get confirmation that it additionally fulfils the requirements of the ISO 9001.

Chapter 4 of ISO/IEC 17025 “Management requirements”

15



Slide 16 In chapter 4.1 of the standard the Organization (Ch. 4.1) requirements on the organization of the legal responsibility (4.1.1) laboratory are described. meeting the requirements of this International Standard, satisfying the needs of the The following themes are addressed: customer, the regulatory authorities or legal responsibility, requirements of organizations providing recognition (4.1.2) The management system shall cover work this International Standard have to be carried out in all facilities: met, needs of the customers, of regula laboratory's permanent facilities, at sites away from its permanent facilities, tory authorities or of organizations or in associated temporary or mobile facilities providing recognition have to be (4.1.3) satisfied. All this must be stated in the quality policy of the laboratory (see 4.2.2 in ISO/IEC 17025). The laboratory management system shall cover all the work carried out, not only in the laboratory's permanent facilities, but also at sites away from its permanent facilities or in associated temporary or mobile facilities. Kaus, R.: Accreditation – ISO/IEC 17025


16



Slide 17 If the laboratory is part of an organization performing activities other than testing and/or calibration, the responsibilities of the key personnel in the organization that have an involvement or influence on the testing and/or calibration activities of the laboratory shall be defined in order to identify potential conflicts of interest.

Organization (Ch. 4.1) Responsibilities of key personnel shall be defined in order to identify potential conflicts of interest (4.1.4)

17



2


25

Slide 18 In the following three slides the requirements for the organisation of the management of the laboratory are described in detail.

Organization (Ch. 4.1) Requirements on the laboratory (4.1.5) (1 of 3) managerial and technical personnel with the authority and resources needed to carry out their duties … management and personnel free from any undue internal and external commercial, financial and other pressures and influences that may adversely affect the quality of their work policies and procedures to ensure the protection of its customers' confidential information and proprietary rights… 18



Slide 19 Organization (Ch. 4.1) Requirements on the laboratory (4.1.5) (2 of 3) policies and procedures to avoid involvement in any activities that would diminish confidence in its competence, impartiality judgement or operational integrity define the organization and management structure of the laboratory, its place in any parent organization, and the relationships between quality management, technical operations and support services specify the responsibility, authority and interrelationships of all personnel who manage, perform or verify work affecting the quality of the tests and/or calibrations 19



Slide 20

Organization (Ch. 4.1) Requirements on the laboratory (4.1.5) (3 of 3) adequate supervision of testing and calibration staff, … technical management with overall responsibility for the technical operations … appoint a member of staff as quality manager … with direct access to highest level of management appoint deputies for key managerial personnel Individuals may have more than one function and it may be impractical to appoint deputies for every function 20



26


Slide 21 Chapter 4.2 demands that the laboratory must have a quality management system appropriate to the scope of its activities. This must be documented in a quality manual which is written in an understandable form and available to all personnel (see chapter 7 in this book).

Management System (Ch. 4.2) Establishing, implementing and maintaining a management system appropriate to the scope of its activities. Documenting its policies, systems, programmes, procedures and instructions to the extent necessary to assure the quality of the test and/or calibration results. The system's documentation shall be communicated to, understood by, available to, and implemented by the appropriate personnel. (4.2.1) 21



Slide 22 In the quality manual the laboratory’s management system policies and objectives shall be defined. The quality policy statement shall be issued under the authority of the top management. For more details on quality manuals see chapter 7.

Management System (Ch. 4.2) Quality manual (4.2.2) The laboratory's management system policies and objectives shall be defined in a quality manual (however named)

Quality policy statement

(4.2.2)

The overall objectives shall be documented in a quality policy statement. The quality policy statement shall be issued under the authority of top management 22



Slide 23 The laboratory's quality policy statement shall at least include the five points listed in the next three slides.

Management System (Ch. 4.2) Contents of the quality policy statement (4.2.2) (1 of 3) It shall include at least the following: the laboratory management's commitment to good professional practice and to the quality of its testing and calibration in servicing its customers the management‘s statement of the laboratory's standard of service 23



2


27

Slide 24

Management System (Ch. 4.2) Contents of the quality policy statement (4.2.2) (2 of 3) the purpose of the management system related to quality a requirement that all personnel concerned with testing and calibration activities within the laboratory familiarize themselves with the quality documentation and implement the policies and procedures in their work; and the laboratory management's commitment to compliance with this International Standard and to continually improve the effectiveness of the management system Kaus, R.: Accreditation – ISO/IEC 17025 In: W enclawiak, Koch, Hadj icostas (eds.)

24


Slide 25

Management System (Ch. 4.2) Contents of the quality policy statement (4.2.2) (3 of 3) Note: The quality policy statement should be concise and may include the requirement that tests and/or calibrations shall always be carried out in accordance with stated methods and customers' requirements. Note: When the test and/or calibration laboratory is part of a larger organization, some quality policy elements may be in other documents. 25



Slide 26 In the predecessor standards and guides (EN 45001 and ISO-Guide 25) there are detailed descriptions of the contents of the quality manual. In ISO/IEC 17025 there are only some general statements about the contents of the manual.

Quality Manual (Ch. 4.2.5 and 4.2.6) The quality manual shall include or make reference to the supporting procedures including technical procedures. It shall outline the structure of the documentation used in the management system. The roles and responsibilities of technical management and the quality manager, including their responsibility for ensuring compliance with this International Standard, shall be defined in the quality manual. 26



28


Slide 27 The requirements on document control are described in chapter 4.3. These requirements are the most difficult parts of the standard for laboratories to implement. In general these requirements are met by preparing an extensive master list.

Document Control (Ch. 4.3) General (4.3.1) (1 of 2) The laboratory shall establish and maintain procedures to control all documents that form part of its management system ⇒ Master list (internally generated or from external sources)

such as regulations, standards, other normative documents, test and/or calibration methods, as well as drawings, software, specifications, instructions and manuals. 27



Slide 28 In a note the term “document” is specified.

Document Control (Ch. 4.3) General (4.3.1) (2 of 2) In this context “document” could be policy statements, procedures, specifications, calibration tables, charts, text books, posters, notices, memoranda, software, drawings, plans, etc. These may be on various media, whether hardcopy or electronic, and they may be digital, analog, photographic or written. The control of data related to testing and calibration is covered in 5.4.7. The control of records is covered in 4.13. 28



Slide 29 The requirements or prerequisites of the Basis Documents are fixed. Basis documents have targets; they can be updated and are applicable over a longer time interval (e.g. standard operation procedures). Proof Documents contain proofs of operations and the details of the actual stock; they are not changeable and are only valid for single incidents (e.g. test reports).

Basis Documents ⇔ Proof Documents Differences Basis Documents

Proof Documents

(4.2.5 quality manual and 4.3 Document control)

(4.13 Control of records)

Requirements or prerequisites Target Changeable Valid for a longer period

Proof Actual stock Not changeable Valid for a single incident

29



2


29

Slide 30 The review of the documents is a strenuous task. In chapter 4.3.2 the requirements for carrying out this review are listed.

Document Approval and Issue (Ch. 4.3.2) Review of the documents (4.3.2.1) The procedure(s) adopted shall ensure that: authorized editions of appropriate documents are available at all locations where operations essential to the effective functioning of the laboratory are performed; documents are periodically reviewed and, where necessary, revised to ensure continuing suitability and complianc e with applicable requirements; invalid or obsolet e documents are promptly removed from all points of issue or use, or ot herwise assured against unintended use; obsolete documents retained for either legal or knowledge preservation purposes are suitably marked. (4.3.2.2) 30


Slide 31 Unique identification is a key requirement for all QS documents.



Document Control (Ch. 4.3) Management system documents generated by the laboratory shall be uniquely identified (4.3.2.3)

31


Slide 32



The policies and procedures for the Review of Requests, Tenders review of requests, tenders and conand Contracts (Ch. 4.4) tracts shall ensure that: Policies and procedures (4.4.1) the requirements, including the Records of reviews (4.4.2) methods to be used, are adequately Review for repetitive routine tasks defined, documented and understood the laboratory has the capability and resources to meet these requirements; an appropriate test and/or calibration method is selected that is capable of meeting the clients’ requirements. Any differences between the request or tender and the contract shall be resolved before any work commences. Each contract shall be acceptable both to the laboratory and the customer. Records of reviews, including any significant changes, shall be maintained. The requirements for the review of requests, tenders and contracts formulated in this standard are hard to fulfil in the routine work of a laboratory. For repetitive routine tasks, the review has to be made only at the initial enquiry stage or on the

32





30


granting of the contract for on-going routine work performed under a general agreement with the customer, provided that the customer's requirements remain unchanged. Slide 33 When a laboratory subcontracts work, either because of unforeseen reasons, or on a continuing basis, this work Subcontracting of Tests and Calibrations (4.5) shall be placed with a competent subcontractor. The subcontractor e.g. Purchasing Services and should comply with ISO/IEC 17025 Supplies (4.6) for the work concerned. The laboratory is responsible to the customer for the subcontractor's work. The laboratory shall maintain a register of all subcontractors that are used for tests and/or calibrations and a record of the evidence of compliance with ISO/IEC 17025. The laboratory shall have a policy and procedure(s) for the selection and purchasing of services and supplies it uses that affect the quality of the tests and/or calibrations. Procedures shall exist for the purchase, reception and storage of reagents and laboratory consumable materials relevant for the tests and calibrations. The laboratory shall evaluate suppliers of critical consumables, supplies and services that affect the quality of testing and calibration, and shall maintain records of these evaluations and a list of those approved. 33





Slide 34 Service to the customer is one of the key elements of this standard. The laboratory shall always have good contacts with its customers to clarify their requests and to monitor the laboratory’s performance. Visits of the customers to the laboratory are welcome, provided that the laboratory is able to ensure the confidentiality of work for other customers.

Service to the Customer (Ch. 4.7) The laboratory shall be willing to cooperate with customers or their representatives in clarifying the customer's request and in monitoring the laboratory's performance in relation to the work performed, provided that the laboratory ensures confidentiality to other customers. 34



2


31

Slide 35 The laboratory shall have a policy and procedure for the resolution of comEnsuring the Quality plaints received from clients or other Complaints (4.8) parties. Records shall be maintained of Control of nonconforming testing and/or all complaints and of the investigations calibration work (4.9) and corrective actions taken by the Improvement (4.10) laboratory. The laboratory shall have a Corrective action (4.11) policy and procedures that shall be Preventive action (4.12) implemented when any aspect of its testing and/or calibration work, or the results of this work, do not conform to its own procedures or the agreed requirements of the client. The policy and procedures shall, among other things, ensure that the responsibilities and authorities for the management of nonconforming work are designated and actions (including halting of work and withholding of test reports and calibration certificates, as necessary) are defined and taken when nonconforming work is identified. In order to reduce the probability of non-conforming work, the laboratory shall continuously improve its management system using appropriate policies, procedures, corrective actions, preventive actions and management reviews. Where an evaluation indicates that the nonconforming work could recur or that there is doubt about the compliance of the laboratory’s operations with its own policies and procedures, the corrective action procedures given in 4.11 shall be promptly followed. The laboratory shall establish a policy and procedure and shall designate appropriate authorities for implementing corrective action when nonconforming work or departures from the policies and procedures in the quality management system or technical operations have been identified. The procedure for corrective action shall start with an investigation determining the root cause(s) of the problem. The laboratory shall monitor the results to ensure that the corrective actions taken have been effective. Where the identification of non-conformances or deviations generates doubts on the laboratory's compliance with its own policies and procedures the laboratory shall ensure that the appropriate areas of activity are audited in accordance with 4.14 (slide 37) as soon as possible. Needed improvements and potential sources of non-conformances either technical or concerning the quality management system, shall be identified. If preventive action is required, an action plan shall be developed, implemented and monitored to reduce the likelihood of the occurrence of such non-conformances and to take advantage of the opportunities for improvement.

35





32


Slide 36 As already mentioned the standard distinguishes between documents and records. Records are proof documents. The laboratory shall establish and maintain procedures for handling such quality and technical records. Quality records shall include reports from internal audits and management reviews as well as records of corrective and preventive actions.

Control of Records (Ch. 4.13) The laboratory shall establish and maintain procedures for identification, collection, indexing, access, fixing, storage, maintenance and disposal of quality and technical records. (4.13.1.1) Quality records shall include reports from internal audits and management reviews as well as records of corrective and preventive actions. 36



Slide 37 Internal audits are very important elements in ensuring that the quality management system is always up to date. The laboratory shall periodically and in accordance with a predetermined schedule and procedure conduct internal audits of its activity to verify that its operations continue to comply with the requirements of the management system and ISO/IEC 17025.

Internal Audits (Ch. 4.14) The laboratory shall periodically and in accordance with a predetermined schedule and procedure conduct internal audits of its activity to verify that its operations continue comply with the requirements of the management system and this International Standard. … (4.14.1) 37



Slide 38 In accordance with a predetermined schedule and procedure, the laboratory’s executive management shall periodically conduct a review as described in the slide.

Management Reviews (Ch. 4.15) Laboratory's top management shall periodically conduct a review of the laboratory's management system and testing and/or calibration activities: ensure their continuing suitability effectiveness, and to introduce necessary changes or improvements. (4.15.1) 38



2


33

Slide 39 In chapter 4.15 the items of a management review are described in detail.

Management Reviews (Ch. 4.15) Review shall take into account (4.15.1):

the suitability of policies and procedures reports from managerial and supervisory personnel the outcome of recent internal audits corrective and preventive actions assessments by external bodies the results of interlaboratory comparisons or proficiency tests changes in the volume and type of the work customer feedback complaints recommendations for improvement other relevant factors, such as quality control activities, resources and staff training. 39


Slide 40 A typical period for conducting a management review is once a year. It is absolutely necessary to have feed back from this review of the laboratory’s work in order to profit from it.



Management Reviews (Ch. 4.15) A typical period for conducting a management review is once every 12 months. Results should feed into the laboratory planning system and should include the goals, objectives and action plans for the coming year. A management review includes consideration of related subjects at regular management meetings. Findings from management reviews and the actions that arise from them shall be recorded. The management shall ensure that those actions are carried out within an appropriate and agreed timescale. (4.15.2) 40



Slide 41 In chapter 5 of ISO/IEC 17025 the “Technical requirements” are described. These are detailed requirements for the special work in the laboratories. They address testing laboratories as well as calibration laboratories. Therefore it is not always easy to distinguish which requirement applies only to calibration laboratories and which to testing laboratories.

Chapter 5 of ISO/IEC 17025 “Technical Requirements”

41



34


Slide 42 In the general chapter the factors that determine the correctness and reliability of the tests and/or calibrations performed by a laboratory are listed together with the chapters in the standard where this aspect is covered.

General (Ch. 5.1) Factors which determine the correctness and reliability of the tests and/or calibrations performed by a laboratory (5.1.1) human factors (5.2) accommodation and environmental conditions (5.3) test and calibration methods and method validation (5.4) equipment (5.5) measurement traceability (5.6) sampling (5.7) the handling of test and calibration items (5.8) 42



Slide 43 The estimation of the total uncertainty is a very important aspect in analytical General (Ch. 5.1) measurements. In the predecessor Influence to the total uncertainty (5.1.2) version of the standard there was only The extent to which the factors contribute to the one sentence about the statement of total uncertainty of measurement differs considerably between (types of) tests and uncertainty (“on demand”). Now the between (types of) calibrations. The laboratory shall take account of these factors estimation of uncertainty as well as the in developing test and calibration methods and procedures, in the training and qualification of establishing of traceability plays a personnel, and in the selection and calibration of the equipment it uses. central role in the ISO/IEC 17025 (see chapters 10 and 12 of this book). The laboratory shall take into account these factors in developing test and calibration methods and procedures, in the training and qualification of personnel, and in the selection and calibration of the equipment used. Kaus, R.: Accreditation – ISO/IEC 17025


43



Slide 44 Personnel (Ch. 5.2) The requirements for personnel are quite demanding and the assessors Requirements for personnel (5.2.1) look in detail at the qualification of the Ensuring the competence of all who operate specific equipment, perform tests and/or personnel. The laboratory management calibrations, evaluate results, and sign test shall ensure the competence of all who reports and calibration certificates. Personnel certification: the laboratory is operate specific equipment, perform responsible for fulfilling specified personnel tests and/or calibrations, evaluate certification requirements. results, and sign test reports and calibration certificates. When staff are used which are still undergoing training, appropriate supervision shall be provided. Kaus, R.: Accreditation – ISO/IEC 17025


44



2


35

Slide 45 The laboratory shall have a training programme for the personnel in which Personnel (Ch. 5.2) the goals are formulated with respect Training programme (5.2.2) to the education, training and skills of Supervising additional personnel (5.2.3) the laboratory personnel. Authorization (5.2.5) If contracted and additional technical and key support personnel are used (e.g. students), the laboratory shall ensure that such personnel are supervised and competent and that they work in accordance with the laboratory’s management system. The management must authorize the personnel to perform specific tasks. The relevant authorization(s), competence, educational and professional qualifications, training, skills and experience of all technical personnel, including contracted personnel shall be recorded. This can be done e.g. on an authorization sheet.

45





Slide 46 Accommodation and environmental Accommodation and conditions in the laboratory shall be Environmental Conditions (Ch. 5.3) such as to facilitate correct perform Laboratory facilities (5.3.1) ance of the tests and/or calibrations. Monitoring the environmental conditions (5.3.2) The laboratory shall ensure that the Tests and calibrations shall be stopped when the environmental conditions jeopardize the results of environmental conditions do not the tests and/or calibrations. (Remember: “No data is better than poor data”) invalidate the results or adversely Preventing cross-contamination (5.3.3) affect the required quality of any Access to the laboratory (5.3.4) Good housekeeping (5.3.5) measurement. This shall be monitored (e.g. min-max thermometer in refrigerators). There must be an effective separation of rooms to prevent cross-contamination, about which measures shall be taken. Particular care shall be taken when sampling and tests and/or calibrations are undertaken at sites other than a permanent laboratory facility. The technical requirements for accommodation and environmental conditions that can affect the results of tests and calibrations shall be documented. The access to the laboratory shall be restricted to authorised personnel only. If customers or other people visit the laboratories they must be accompanied. The extent of control is based on the particular circumstances. Measures shall be taken to ensure good housekeeping in the laboratory. Special procedures shall be prepared where necessary, e.g. in microbiological laboratories. 46





36


Slide 47 The laboratory shall use appropriate Test and Calibration Methods methods and procedures for all tests and Method Validation (Ch. 5.4) and/or calibrations within its scope. General (5.4.1) These include sampling, handling, Using appropriate methods and procedures for all transport, storage and preparation of tests and/or calibrations within its scope. The laboratory shall have instructions on the use items to be tested and/or calibrated, and operation of all relevant equipment, and on the handling and preparation of items for testing and, where appropriate, an estimation and/or calibration, of the measurement uncertainty (see shall be kept up to date and shall be made readily available to personnel chapter 12 of this book) as well as statistical techniques for analysis of test and/or calibration data. The laboratory shall have instructions on the use and operation of all relevant equipment, and on the handling and preparation of items for testing and/or calibration, or both, where the absence of such instructions could jeopardize the results of tests and/or calibrations. All instructions, standards, manuals and reference data relevant to the work of the laboratory shall be kept up to date and shall be made readily available to personnel (see also 4.3 in ISO/IEC 17025). Deviations from test and calibration methods shall only occur if the deviation has been documented, technically justified, authorized, and accepted by the client. 47





Slide 48 The laboratory shall use methods, Test and Calibration Methods which meet the needs of the customer and Method Validation (Ch. 5.4) and which are appropriate for the tests Selection of methods (5.4.2) and/or calibrations it undertakes. Laboratory developed methods (5.4.3) Standard methods (international, Non-standard methods (5.4.4) regional or national) shall preferably Validation of methods (5.4.5) be used. The laboratory shall ensure Estimation of uncertainty of that it uses the latest valid edition of a measurement (5.4.6) standard unless it is not appropriate or Control of data (5.4.7) possible to do so. If no standard methods exist or if they are not appropriate, laboratory developed or other non-standard methods that are suitable for the special task and which are validated can be used. Validation of methods is an important task in the laboratory (see chapter 11). The degree of rigour needed in estimating the uncertainty of measurement considerably differs between calibration and testing laboratories. For testing methods it depends on factors such as: the requirements of the test method, the requirements of the customer, the existence of narrow limits on which decisions or conformance to a specification are based.

48





2


37

Calculations and data transfers shall be controlled in a systematic manner. Nowadays nearly all analytical measurements are made with computer-aided or automated equipment. The laboratory shall ensure the proper functioning to maintain the integrity of test and calibration data. Commercial software (e.g. word processing, database and statistical programmes) may be considered to be sufficiently validated. However, there may be a need to validate laboratory software configuration/modifications. Slide 49 The records of equipment shall include a lot of detailed information.

Equipment (Ch. 5.5) Records of Equipment (5.5.5) The records shall include at least the following: the identity of the item of equipment and its software the manufacturer's name, type identification, and serial number or other unique identification checks that equipment complies with the specification the current location, where appropriate the manufacturer's instructions, if available, or reference to their location dates, results and copies of reports and certificates of all calibrations, adjustments, acceptance criteria, and the due date of next calibration the maintenanc e plan, where appropriate, and maintenance carried out to date any damage, malfunction, modification or repair to the equipment 49


Slide 50



Establishing the traceability of the measurement is one of the most imporMeasurement Traceability (Ch. 5.6) tant requirements in ISO/IEC 17025. The laboratory shall have an established Measurement traceability ensures that programme and procedure for the calibration of its equipment. the measurements in different labora Such a programme should include a system tories are comparable in “space and for selecting, using, calibrating, checking, controlling and maintaining measurement time” all over the world. Calibration standards, reference materials used as measurement standards, and measuring and and the use of certified reference test equipment used to perform tests and material (see chapters 9, 10 and 14) is calibrations. … the central tool in establishing traceability. Therefore a laboratory must have programmes and procedures for both. Kaus, R.: Accreditation – ISO/IEC 17025


50



38


Slide 51 The programmes for calibration of equipment shall be designed and Measurement Traceability (Ch. 5.6) operated in a way to ensure that cali Specific requirements (5.6.2) brations and measurements made by for calibration laboratories the calibration laboratory are traceable traceable to the International System of Units (SI) (Systeme international d'unites). (5.6.2.1.1) to the International System of Units Testing (5.6.2.2) (SI) (Système international d'unités). Reference standards and reference For testing laboratories, the extent to materials (5.6.3) which the requirements in establishing traceability should be followed depends on the relative contribution of the calibration uncertainty to the total uncertainty. lf calibration is the dominant factor, the requirements should be strictly followed. Where traceability of measurements to SI units is not possible and/or not relevant, the same requirements for traceability to, for example, certified reference materials, agreed methods and/or consensus standards, are required as for calibration laboratories. The laboratory shall have a programme and procedure for the calibration of its reference standards. A body that can provide traceability shall calibrate reference standards. Such reference standards of measurement held by the laboratory shall be used for calibration only and for no other purpose, unless it can be shown that their performance as reference standards would not be invalidated. The laboratory shall have procedures for safe handling, transport, storage and use of reference standards and reference materials in order to prevent contamination or deterioration and in order to protect their integrity. 51





Slide 52 Sampling is a defined procedure whereby a part of a substance, material Further Chapters or product is taken as a representative Sampling (Ch. 5.7) sample of the whole for testing or Handling of test and calibration items calibration. The laboratory shall have (Ch. 5.8) sampling plans and procedures. They Assuring the quality of test and calibration results (Ch. 5.9) must be available at the location where sampling is undertaken. Sampling plans shall, whenever reasonable, be based on appropriate statistical methods. Any deviations, additions or exclusions from the documented sampling procedure shall be recorded in detail with the appropriate sampling data and shall be included in all documents containing Kaus, R.: Accreditation – ISO/IEC 17025


52



2


39

test and/or calibration results, and shall be communicated to the appropriate personnel. The laboratory shall have procedures for the handling (e.g. transportation, protection, storage, disposal) of test and/or calibration items. To ensure the trackability (traceability to the raw data) of analytical results, the laboratory shall have a system to identify test and/or calibration items uniquely. The identification shall be retained throughout the life of the item in the laboratory. All abnormalities or deviations from normal or specified conditions, as described in the test or calibration method, shall be recorded. When there is doubt on the suitability of an item for test or calibration, the laboratory shall consult the client for further instructions before proceeding and shall record the discussion. The laboratory shall have quality control procedures for monitoring the validity of tests and calibrations undertaken. Trends should be detectable and, where practicable, statistical techniques shall be applied to the reviewing of the results (see chapter 12). Slide 53 The results shall be reported in a test report or a calibration certificate, and Reporting the Results (Ch. 5.10) shall include all the information shall be reported requested by the customer and necessary accurately, for the interpretation of the test or clearly, calibration results and all information unambiguously objectively required by the method used. in accordance with any specific In some cases (written agreement with instructions in the test or calibration the client) the results may be reported methods. in a simplified way, but any information listed in 5.10.2 to 5.10.4 (see following slides) that is not reported to the client shall be readily available in the laboratory. Kaus, R.: Accreditation – ISO/IEC 17025


Slide 54 In chapter 5.10.2 of ISO/IEC 17025 the form of the test reports and calibration certificates are specified in detail. The first points (title, name of laboratory and client, serial number, method) are necessary to guarantee unique identification.

53



Reporting the Results (Ch. 5.10) Test Reports and Calibration Certificates (5.10.2) (1 of 3)

Each test report or calibration certific ate shall include at least the following information, unless the laboratory has valid reasons for not doing so: a title (e.g. “Test Report” or “Calibration Certificate”) the name and address of the laboratory, and the location where the tests and/or calibrations were carried out, if different from the address of the laboratory unique identification of the test report or calibration certificate (such as the serial number), and an each page an identification in order to ens ure that the page is recogniz ed as a part of the test report or calibration certificat e, and a clear identification of the end of the test report or calibration certificat e the name and address of the customer identification of the method used 54



40


Slide 55 The following slides contain the details of the information that usually have to be included in the test or calibration certificate. These include the date of the measurement, the result, the staff responsible for carrying out the work and where relevant a statement that the results apply to the items tested or calibrated.

Reporting the Results (Ch. 5.10) Test Reports and Calibration Certificates (5.10.2) (2 of 3) a description of, the condition of, and unambiguous identification of the item(s) tested or calibrated the date of receipt of the test or calibration item(s) where this is critical to the validity and application of the results, and the date(s) of performance of the test or calibration reference to the sampling plan and procedures used by the laboratory or other bodies where these are relevant to the validity or application of the results the test or calibration results with, where appropriate, the units of measurement the name(s), function(s ) and signature(s) or equivalent identification of person(s) authorizing the test report or calibration certificat e where relevant, a statement to the effect that the results relate only to the items tested or calibrated 55



Slide 56 In a note to chapter 5.10.2 of ISO/IEC 17025 details of the certificates/reports are specified, including the need to number each page and to give the total number of pages. A statement specifying that the test report or calibration certificate shall not be reproduced except in full, without written approval of the laboratory should be included in the document (e.g. as a footnote).

Reporting the Results (Ch. 5.10) Test Reports and Calibration Certificates (5.10.2) (3 of 3)

Hard copies of test reports and calibration certificates should also include the page number and total number of pages. It is recommended that laboratories include a statement specifying that the test report or calibration certificate shall not be reproduced except in full, without written approval of the laboratory 56



Slide 57 In the preceding version of the standard it was strictly forbidden to give any interpretation of the results within the test report. Now it is explicitly allowed. In addition to the necessary requirements as listed above, test reports can, include the items listed in this slide.

Reporting the Results (Ch. 5.10) Test Reports (5.10.3)

In addition to the requirements listed in 5.10.2, test reports shall, where necessary for the interpretation of the test results, include the following: deviations from, additions to, or exclusions from the test method, and information an specific test conditions, such as environmental conditions; Where relevant, a statement of compliance/non-c ompliance with requirements and/or specifications; where applicable, a statement on the estimated uncert ainty of measurement; information on uncertainty is needed in test reports when it is relevant to the validity or application of the test results, when a customer's instruction so requires, or when the uncertainty affects complianc e to a specification limit; where appropriate and needed, opinions and interpretations (see 5.10.5); additional information which may be required by specific methods, customers or groups of customers. (5.10.3.1) Kaus, R.: Accreditation – ISO/IEC 17025 In: W enclawiak, Koch, Hadj icostas (eds.)

57


2


41

Slide 58 If test reports contain the results of sampling they shall include additional information about the sampling.

Reporting the Results (Ch. 5.10) Test Reports (5.10.3) the results of sampling shall include the following, where necessary for the interpretation of test results: the date of sampling unambiguous identification of the substance, material or product sampled (including the name of the manufacturer, the model or type of designation and serial numbers as appropriate) the location of sampling, including any diagrams, sketches or photographs a reference to the sampling plan and procedures used details of any environmental conditions during sampling that may affect the interpretation of the test results any standard or other specification for the sampling method or procedure, and deviations, additions to or exclusions from the specification concerned. (5.10.3.2) 58


Slide 59 In addition to the requirements listed in clause 5.10.2 of ISO/IEC 17025, calibration certificates shall include conditions under which the calibration was carried out, the uncertainty on the result and information about the measurement traceability, which is necessary for the interpretation of calibration results.



Reporting the Results (Ch. 5.10) Calibration Certificates (5.10.4) shall include: the conditions (e.g. environmental) under which the calibrations were made that have an influence an the measurement results the uncertainty of measurement and/or a statement of compliance with an identified metrological specification or clauses thereof evidence that the measurements are traceable

59



Slide 60 When opinions and interpretations are included, the laboratory shall document the basis upon which the opinions and interpretations have been made. Opinions and interpretations shall be clearly marked as such in a test report.

Reporting the Results (Ch. 5.10) Opinions and Interpretations (5.10.5)

Documenting the basis upon which the opinions and interpretations have been made Opinions and interpretations shall be clearly marked as such in a test report.

60



42


Slide 61 Opinions and interpretations should not be confused with inspections and product certifications as intended in ISO/IEC 17020 and ISO/IEC Guide 65. Opinions and interpretations included in a test report may comprise, but not be limited to those listed in the slide.

Reporting the Results (Ch. 5.10) Opinions and Interpretations (5.10.5) No confusion with inspections and product certifications as intended in ISO/IEC 17020 and ISO/IEC Guide 65 (5.10.5 Note 1) Possible contents: an opinion on the statement of compliance/noncompliance of the results with requirements fulfilment of contractual requirements recommendations and how to use the results guidance to be used for improvements (5.10.5 Note 2) 61


Slide 62



When the test report contains results of tests performed by subcontractors, Reporting the Results (Ch. 5.10) these results shall be clearly identified. Testing and calibration results obtained Many laboratories have problems with from subcontractors (5.10.6) this requirement, because they are Clear Identification afraid of the possibility that the clients Electronic transmission of results (5.10.7) would have doubt about their own Requirements of this International Standard shall be met (see also 5.4.7) competence or that the client could transfer their orders directly to subcontractors. In the case of transmission of test or calibration results by telephone, telex, facsimile or other electronic or electromagnetic means, the requirements of this International Standard shall be met. The transmission must be done in a way that meets the requirements of the customer. Kaus, R.: Accreditation – ISO/IEC 17025


62



Slide 63 The format shall be designed to Reporting the Results (Ch. 5.10) accommodate each type of test or Format of Reports and Certificates (5.10.8) calibration carried out and to minimize Accommodating each type of test or the possibility of misunderstanding or calibration carried out misuse. Minimizing the possibility of misunderstanding or misuse. Attention should be given to the layout Headings should be standardized as far of the test report or calibration certifias possible. cate, especially with regard to the presentation of the test or calibration data and ease of assimilation by the reader. The headings should be standardized as far as possible. Kaus, R.: Accreditation – ISO/IEC 17025


63



2


43

Slide 64 If there are amendments to test reports Reporting the Results (Ch. 5.10) Amendments to Test Reports and or calibration certificates after issue, Calibration Certificates (5.10.9) they shall be made only in the form of Material amendments shall include the a further document. It must contain a statement: statement to which document the “Supplement to Test Report [or Calibration Certificate], serial number ... [or as otherwise amendment belongs. identified]”, … If there are too many corrections it is When it is necessary to issue a complete new test report or calibration certificate, this shall sometimes necessary to write a be uniquely identified and shall contain a reference to the original that it replaces completely new test report or calibration certificate. This new document shall be uniquely identified and shall contain a reference to the original that it replaces. Kaus, R.: Accreditation – ISO/IEC 17025


64



Slide 65 As can be seen from the previous slides, preparation for accreditation is Summary a tremendous amount of work. Never Preparation for accreditation according theless it will be increasingly necesto ISO/IEC 17025 is not an easy task, sary for laboratories, especially if they especially when done for the first time. want to be active in different But it assures at most customers confidence about quality and correct countries. procedures. The accreditation according to ISO/IEC 17025 (or ISO 15189 for medical laboratories) has turned out to be the most important and worldwide valid standard for competent testing and calibration laboratories. Kaus, R.: Accreditation – ISO/IEC 17025


65



Slide 66 More guidance on the way to accreditation may be found in the CITAC/EURACHEM guide mentioned here and the literature listed below.

More Guidance For laboratories preparing for accreditation according to ISO/IEC 17025 more guidance can be found in: CITAC/EURACHEM-Guide: Guide to Quality in Analytical Chemistry - An Aid to Accreditation, 2002, available from http://www.eurachem.org 66



44


Bibliography CITAC/EURACHEM (2002) Guide to Quality in Analytical Chemistry – An Aid to Accreditation, available from www.eurachem.org Günzler H (1996) Accreditation and Quality Assurance in Analytical Chemistry, Springer, Berlin ISO/IEC 17000:2004 - Conformity assessment - Vocabulary and general principles ISO/IEC 17011:2004 - Conformity assessment - General requirements for accreditation bodies accrediting conformity assessment bodies ISO 17020:1998 - General criteria for the operation of various types of bodies performing inspection ISO/IEC 17025:2005 - General requirements for the competence of testing and calibration laboratories ISO 15189:2007 - Medical laboratories -- Particular requirements for quality and competence ISO/IEC Guide 65:1996 - General requirements for bodies operating product certification systems Wilson S, Weir G (1995) Food and Drink Laboratory Accreditation: A Practical Approach, Springer-Verlag, Berlin

3

ISO 9000 Quality Management System

Evsevios Hadjicostas The ISO 9000 series describes a quality management system applicable to any organization. In this chapter we present the requirements of the standard in a way that is as close as possible to the needs of analytical laboratories. The sequence of the requirements follows that in the ISO 9001:2008 standard. In addition, the guidelines for performance improvement set out in the ISO 9004 are reviewed. Both standards should be used as a reference as well as the basis for further elaboration. Slide 1 A laboratory product is the result, including intermediary results, of any Definitions laboratory process, e.g. the result of an The laboratory product analysis. A laboratory process is any The laboratory process activity employed for the production The laboratory customer of the analysis results, e.g. the perform The satisfaction ance of an analysis etc. The laboratory The improvement customers are those having an interest in the analysis results. “The satisfaction” refers to the laboratory customers and interested parties as to the quality of both the laboratory products and laboratory processes. “The improvement” refers to the laboratory objective to achieve excellence through the continuous improvement of its products and processes. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

1




45

46


Slide 2 A laboratory accepts inputs, adds value to these inputs and produces outputs for the customers. Inputs are such as reagents, samples, methods, instruments, i.e. what is necessary for the proper operation of the laboratory. The output is what is supplied to the customer, i.e. the analysis results and expert opinion. Elements associated with the process are the following: people, equipment, materials and environment.

The Process Approach Controls

Inputs

Outputs

Process

Resources

2

Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)


Slide 3 The requirements of the standard can Model of a Process-based Quality Management System Continual be split into four major groups, which Continualimprovement improvementof ofthe thequality quality management managementsystem system are those mentioned as “activities” in Interested Interested Interested Interested parties parties the quality management process. A parties parties fifth group is the quality management system per se. The model shown in the slide, taken from the ISO 9004: 2000 standard, illustrates the process linkages as well as the interactions between the interested parties and the laboratory. Monitoring the satisfaction of interested parties requires the evaluation of information as to whether the laboratory has met their requirements. Manag Management ement Responsibility Responsibility

Resource Resource Manag Management ement

Requirements Requirements

Input

Value-adding activities


Measurement Measurement Analy Analysis sisand and Improv Improvement ement

Product Product Realization Realization

Information flow

Satisfaction Satisfaction

Product Product

Output

f rom ISO 9004:2000



3

3


47

Slide 4 The first requirements are concerned with the quality management system (QMS) and the documentation that is necessary for the effective operation of the system, which is quite substantial. The numbering of the paragraphs is the same as in the standard to make it easier to look up further details.

4 Quality Management System 4.1 General requirements 4.2 Documentation requirements

4.2.1 General 4.2.2 Quality manual 4.2.3 Control of documents 4.2.4 Control of records

4



Slide 5 The laboratory shall establish, docu4 QUALITY MANAGEMENT SYSTEM ment, implement and maintain a QMS 4.1 General Requirements and continually improve its effective Quality management system (QMS) ness. Laboratory processes are managed Continual improvement in a way that ensures the effectiveness Sequence and interaction of processes Effective operation and control of processes of the QMS and the continual improve Availability of resources and information ment of the laboratory operation. The Monitor, measure and analyze processes Achieve planned results laboratory processes and their Improve processes Outsourcing of processes sequence and interaction shall be defined and their effective operation shall be considered. Such effectiveness is ensured by the provision of the necessary resources and information. The effective operation of the laboratory processes is monitored on the basis of the achievement of the planned results. The output of this monitoring process is the improvement in the overall laboratory function. The defined systems and processes of the laboratory QMS need to be simple so as to be clearly managed and understood. However, complicated processes often need a great deal of attention to simplify their operation. Any laboratory processes that are outsourced shall be identified within the QMS and the laboratory shall ensure control over such processes. Such a control depends on the significance of the outsourced activities to the conformity of the result to defined requirements. The degree and extent of control exerted to outsourced activities is defined and documented to the QMS. 5




48


Slide 6 The laboratory management shall 4 QUALITY MANAGEMENT SYSTEM define the documentation and records 4.2 Documentation Requirements needed to establish, implement and 4.2.1 General maintain the QMS and support an Quality policy effective and efficient operation of Quality objectives the laboratory processes. A statement Quality manual of the quality policy and quality Procedures objectives conveys the management Work instructions commitment to quality and the Records customer oriented practices. The entire QMS is defined and documented in the quality manual, which is the top level document of the system. The quality manual is connected to the procedures, work instructions and other supporting documents that make the quality system operate. Records from all vital activities are used as evidence of the effective operation of the system. 6




Slide 7 The laboratory quality manual is a 4 QUALITY MANAGEMENT SYSTEM document addressing the quality 4.2 Documentation Requirements management system requirements and 4.2.2 Quality manual shall The laboratory quality manual shall refer to the scope of the QMS, include: make reference to the laboratory The scope of the quality management system procedures and Links to the laboratory procedures describe the interaction between Interactions between the processes of the the processes of the QMS. QMS The Quality Manual is the top level document of the laboratory and can be used to substantiate the compliance of the laboratory to the QMS requirements (see chapter 7). Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)



7

3


49

Slide 8 The documents required by the QMS 4 QUALITY MANAGEMENT SYSTEM shall be controlled. Such control is 4.2 Documentation Requirements necessary to approve, review and 4.2.3 Control of documents update the documents and to identify Approval of documents Review, update and re-approval of documents changes and amendments. Documents Identification of changes and current revisions that are used for the operation of the Availability of documents at points of use Documents to be legible and readily QMS shall be available at points of identifiable use and understood by the personnel Control of external documents Control of obsolete documents that uses this documentation. Achieves Documents of external origin must be identified and their distribution must be controlled. Obsolete documents must be prevented from unintended use and easily identified and controlled. The achieving system is considered as part, and thus, being under the control of the QMS. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 9 Records are considered as a special type of documents and shall therefore be identifiable and properly controlled. The system for their storage, protection, retrieval, and for their retention time and disposition is documented in written procedures. The laboratory records provide objective evidence of conformity to requirements and of the effective operation of the QMS. Slide 10

8



4 QUALITY MANAGEMENT SYSTEM 4.2 Documentation Requirements 4.2.4 Control of records Objective evidence of conformity to requirements Legible, readily identifiable, retrievable Documented procedure for the identification, storage, protection, retrieval, retention time and disposition of records 9



5 Management Responsibility 5.1 Management commitment 5.2 Customer focus 5.3 Quality policy 5.4 Planning

5.5 Responsibility, authority and communication

The introduction of the QMS is a sig 5.5.1 Responsibility and authority nificant investment for the organization 5.5.2 Management representative and needs resources and effort to be 5.4.1 Quality objectives 5.5.3 Internal communic ation 5.4.2 Quality 5.6 Management review disseminated throughout the organizamanagement system 5.6.1 General planning 5.6.2 Review input tion. For this reason, management 5.6.3 Review output responsibility is the primary element of the QMS that needs to be defined. These are the elements that need to be addressed by the management. Details of each element and how they are addressed by the management are given below. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

10



50


Slide 11 Leadership, commitment and active involvement of the top management 5 MANAGEMENT RESPONSIBILITY are essential for developing and main5.1 Management Commitment taining an effective and efficient QMS Addressing customer requirements to achieve benefits for laboratory Establishing the quality policy customers and interested parties. Top Ensuring that quality objectives are established management and leaders establish Conducting management reviews unity of purpose and directions as well Ensuring the availability of resources as the vision, policies and strategic objectives of the laboratory. They create and maintain the internal environment and urge people to become fully involved in achieving the quality objectives and satisfying customer’s requirements. They define methods for measurement of the laboratory performance and plan for the future. They provide for the necessary resources and they review the operation of the QMS to continually improve its effectiveness. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

11



Slide 12 The success of the laboratory depends on understanding and satisfying the current and future needs and expectations of present and potential customers and other interested parties. The interested parties of the laboratory are the customers (internal and external), people in the laboratory and the whole organization in general, the owners and investors, the suppliers and partners and the society and the environment.

5 MANAGEMENT RESPONSIBILITY 5.2 Customer Focus Satisfaction of the needs and expectation of the current and future customers Internal and external customers The interested parties

12



3


51

Slide 13 Quality policy is the commitment of 5 MANAGEMENT RESPONSIBILITY management that the laboratory is 5.3 Quality Policy seeking continuous improvement. This Appropriate to the purpose of the laboratory policy includes the vision and strategy Commitment to compliance with requirements of the organization and makes it clear How quality objectives are established and reviewed to interested parties that it is deter Communicated and understood within the mined to succeed. laboratory The laboratory quality policy should Reviewed for continuing suitability be appropriate to the purpose of the laboratory and should include the commitment to quality and compliance with the system requirements. The quality policy shall provide a framework for establishing and reviewing quality objectives. It shall be communicated and understood within the organization and it is subject to systematic review for continuing suitability. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

13



Slide 14 The laboratory should focus on defin5 MANAGEMENT RESPONSIBILITY ing the processes needed to meet 5.4 Planning effectively and efficiently the quality 5.4.1 Quality objectives objectives and the requirements The quality objectives of the various consistent with the strategy of the functions and levels within the laboratory. The establishment of the laboratory shall be established and be consistent with the quality policy and the quality planning is based on the inputs laboratory strategy and needs for such a planning to be in place. The implementation of the quality planning is based on the outputs, i.e. the necessary resources needed for the plan to be realized. The quality objectives are defined with the contribution of the interested parties, especially those that are bound to accomplish these objectives. They shall be measurable and consistent with the quality policy. Both the quality policy and quality objectives shall be communicated and understood within the laboratory and reviewed for continuing suitability. The quality objectives are established at relevant functions and levels within the laboratory based on the feedback taken from relevant findings from management reviews, from current performance, from self-assessment etc. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

14



52


Slide 15 Quality planning in a laboratory is the 5 MANAGEMENT RESPONSIBILITY process needed to meet the labora5.4 Planning tory’s quality objectives. An effective 5.4.2 Quality management system planning and efficient planning consists of the Meet the general requirements for the inputs (strategies and objectives, quality management system (4.1) customers’ needs and expectation, Management of change evaluation of data etc.) and the outputs (needs for resources, needs for improvement, etc.). Changes in the QMS must be effectively and efficiently managed so that the integrity of the system is maintained and it continues to improve and conform to the requirements. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 16 Laboratory personnel should be given appropriate responsibility and authority to be motivated, committed and actively involved in contributing to the achievement of the quality objectives. The responsibilities and authorities of laboratory personnel shall be defined, communicated and agreed with interested individuals. Slide 17

15



5 MANAGEMENT RESPONSIBILITY 5.5 Responsibility, Authority and Communication

5.5.1 Responsibility and authority Responsibilities and authorities of laboratory personnel should be defined and communicated within the laboratory 16



5 MANAGEMENT RESPONSIBILITY 5.5 Responsibility, Authority and Communication

The management representative is the 5.5.2 Management representative person appointed by the top manage Member of the organization Ensures the proper operation of the quality ment to implement the policy, monimanagement system tor, evaluate and coordinate the QMS. Reports to the top management The management representative shall Promotes the awareness of customer requirements throughout the organization be a member of the organization and such activity cannot be outsourced. He or she ensures that the processes needed for the proper operation of the QMS are established, implemented and maintained. He or she reports to the top management on the performance of the QMS. The management representative is the person that promotes the image of the laboratory to the internal as well as the external environment of the laboratory.

17




3


53

Slide 18 The laboratory top management establishes communication channels within the laboratory departments that ensure effective and efficient operation of the laboratory. Activities that help communication include for example, meetings, information on notice boards, a “laboratory journal”, e-mails and web sites, employee surveys and suggestion schemes etc.

5 MANAGEMENT RESPONSIBILITY 5.5 Responsibility, Authority and Communication 5.5.3 Internal communication Communication channels within the laboratory Communication as the stimulus for an effective QMS

18



Slide 19 Management systematically reviews the realization of processes and evaluates the efficiency of the system by conducting management reviews. Management reviews are platforms for the exchange of new ideas, with open discussions being stimulated by the leadership of top management. The management reviews are conducted at planned intervals and include assessment of opportunities for improvement and the need for changes of the QMS.

5 MANAGEMENT RESPONSIBILITY 5.6 Management Review 5.6.1 General Review of the system at planned intervals Assessment of opportunities for improvement Needs for changes Records of management reviews 19



Slide 20 Management reviews are conducted 5 MANAGEMENT RESPONSIBILITY based on the “review inputs” and any 5.6 Management Review decisions and actions taken as a result 5.6.2 Review input of the management review are the Results of audit and self-assessment “review output”. The information Feedback from customer and from taken as input to the management benchmarking activities Performance of the laboratory activity reviews could be the results from audits Any recommendations for improvement and self-assessment of the laboratory, (corrective and preventive actions, feedback from customers and results suggestions from laboratory personnel) from benchmarking activities, the laboratory activity performance, the status of corrective and preventive action etc. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

20



54


Slide 21 The top management shall use the outputs of the management reviews as inputs to improvement of processes and resource needs. The decisions made in the management review meetings could be used to set up the laboratory objectives and form the laboratory strategy.

5 MANAGEMENT RESPONSIBILITY 5.6 Management Review 5.6.3 Review output Decisions and actions resulted from the management review meetings that will improve the effectiveness of the system and the quality of the laboratory product

21

Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System

Slide 22 Now that the management is committed to quality and organized to put the system in place, there is the need to provide the necessary resources including human resource, infrastructure, work environment, information and, of course, financial resources.



6 Resource Management 6.1 Provision of resources 6.2 Human resources 6.2.1 General 6.2.2 Competence, awareness and training

6.3 Infrastructure 6.4 Work environment 22


Slide 23



It is the responsibility of the laboratory 6 RESOURCE MANAGEMENT management to ensure that the neces6.1 Provision of Resources sary resources essential to the imple Provision of the resources needed for: mentation of strategy and laboratory The implementation and maintenance of objectives and the realization of the QMS customer satisfaction are identified Realization of customer satisfaction and made available. Resources may be people, infrastructure, work environment, information, suppliers and partners, natural resources and financial resources. The provision of resources is supplied in relation to the opportunities and constraints that the laboratory faces. Amongst the resources are included tangible and intangible resources (such as intellectual properties), information management and technology, enhancement of competence via training and learning, use of natural resources etc. 23




3


55

Slide 24 Laboratory personnel which affect the quality of the results as well as the conformity of such results to specified requirements shall be competent enough. The laboratory shall encourage the involvement and development of its people by providing ongoing training, by defining their responsibilities and authorities, by facilitating involvement in objective setting and decision making, by recognizing and rewarding etc.

6 RESOURCE MANAGEMENT 6.2 Human Resources 6.2.1 General Appropriate education, training, skills and experience of the laboratory personnel

24



Slide 25 The laboratory management shall 6 RESOURCE MANAGEMENT determine the necessary competence 6.2 Human Resources of people working in the laboratory 6.2.2 Competence, awareness and training and ensure that it is available for the Determination of necessary competence of effective and efficient operation of the the laboratory personnel Provision of training laboratory. Improvement of people’s Evaluation of the effectiveness of the action competence comes through awareness taken Awareness of personnel of the relevance and and training. The management of the importance of their activities laboratory should encourage people to Maintenance of training records develop through training and education programs, which are relevant to the needs of the laboratory. The effectiveness of training and education is evaluated and people are urged to strengthen the knowledge gained from training and education courses.

25


Slide 26 Infrastructure includes resources such as buildings, equipment, supporting services, information and communication technology etc. The infrastructure shall be determined, provided and maintained so that the laboratory product conforms to specified requirements.



6 RESOURCE MANAGEMENT 6.3 Infrastructure Building and workspace Process equipment Supporting services (transportation, communication) Information systems

26



56


Slide 27 Work environment motivates and enhances satisfaction and performance of people. A suitable work environment considers factors such as hygiene, cleanliness, absence of noise, vibration or pollution, heat, humidity, light, airflow, ergonomics, workplace location, and facilities for laboratory personnel safety rules, social interactions etc.

6 RESOURCE MANAGEMENT 6.4 Work Environment The work environment in the laboratory shall be determined and managed in a way to encourage people in achieving conformity to product requirements

27



Slide 28 The product realization is the main part of the QMS activity. Product 7 Product Realization realization in the case of a laboratory 7.1 Planning of 7.3 Design and development is the process of performing the analysis. product realization 7.3.1 Design and development planning 7.2 Customer 7.3.2 Design and development inputs First, the laboratory plans its activities related processes 7.3.3 Design and development output 7.2.1 Determination 7.3.4 Design and development review and then it determines the customer of requirements related to product 7.3.5 Design and development verification related process, defines the analysis 7.2.2 Review of requirements related 7.3.6 Design and development to product validation requirements and develops the 7.2.3 Customer 7.3.7 Control of design and communication development changes communication channels with the customers. The third stage is to design and develop new products, i.e. new methods and new analysis processes if necessary or if so required. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

28



Slide 29 7 Product Realization At the fourth stage the laboratory develops the purchasing activities, i.e. it 7.5.2 Validation of 7.4 Purchasing processes for production 7.4.1 Purchasing defines the purchasing processes, and service provisions processes 7.4.2 Purchasing 7.5.3 Identification and collects purchasing information and veriinformation traceability 7.4.3 Verification of 7.5.4 Customer property fies the purchased products. The fifth purchased products 7.5.5 Preservation of 7.5 Product and service product step is to define the system of perprovision 7.6 Control of 7.5.1 Control of monitoring and forming the laboratory activity, valiproduction and service measuring devices provisions date such activities, keep records and trace back to raw data. The laboratory instruments must be calibrated and always be monitored for their proper operation. 29




3


57

Slide 30 The laboratory should specify and document the laboratory processes 7 PRODUCT REALIZATION (e.g. the analytical methods) and the 7.1 Planning of Product Realization laboratory resources (instruments, Quality objectives and product specification equipment etc.) that are necessary to Establishment of processes and documents and provision of resources specific to the produce the laboratory product i.e. the product analysis results. Verification, validation, monitoring, inspection, and test activities specific to the product and The quality plan defines the inputs and Criteria for product acceptance outputs of any laboratory process. For Records example, the quality plans refer to the analytical methods, the instruments and laboratory equipment that are used for the analysis, the characteristics of the analysis results etc. All laboratory processes (e.g. analytical methods) and laboratory products (e.g. analytical results) should be subject to verification and validation to ensure that they are fit for the purpose. The acceptance criteria should be defined and records should always be kept as evidence of meeting the requirements.

30




Slide 31 The laboratory shall ensure that there 7 PRODUCT REALIZATION is an effective and efficient communi7.2 Customer Related Processes cation with its customers so that the 7.2.1 Determination of requirements related analysis requirements are unambiguous to the product and well understood by the customer. Requirements specified by the customer The laboratory shall provide for Requirements necessary for specified or intended use customer satisfaction as to the apparent Statutory and regulatory requirements as well as to the hidden customer Requirements determined by the requirements. The analysis process organization must always be performed based on the relevant statutory and regulatory requirements. Any requirements determined by the organization under which the laboratory operates must also be considered. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

31



58


Slide 32 Customer requirements are explicit 7 PRODUCT REALIZATION and implicit. The laboratory shall 7.2 Customer Related Processes review the requirements specified by 7.2.2 Review of requirements related to the the customer prior to commitment to product Definition of product requirements undertake the job and ensure that it has Resolution of contract or order requirements the ability to meet the defined Ability to meet the defined requirements Records of the results of the review and action requirements. Anything that is dis Confirmation of customer requirements and cussed and agreed with the customer is re-confirmation in case of changes Awareness of relevant personnel confirmed and recorded. If any changes to agreed requirements occur, the laboratory shall ensure that the relevant documents are amended and that the relevant personnel are made aware of the changed requirements. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

32



Slide 33 Communication with customers is vital for the improvement of the laboratory performance regarding services as well as the quality of analytical results. Such communication keeps the relationship live and establishes the reputation of the laboratory.

7 PRODUCT REALIZATION 7.2 Customer Related Processes 7.2.3 Customer communication The laboratory shall communicate with its customers to get information on the laboratory products and feedback from customers including customer complaints 33



Slide 34 The laboratory activity and its services 7 PRODUCT REALIZATION to customers are designed and devel7.3 Design and Development oped so as to respond effectively and 7.3.1 Design and development (D&D) efficiently to the needs and expectaplanning tions of its customers and interested Design and development stages parties. Factors such as safety and Review, verification and validation health, testability, usability, user Responsibilities and authorities Effective communication between D&D friendliness, the environment and groups identified risks should be considered Update of planning output when designing the laboratory process. The laboratory shall plan and control the design and development (D&D) stages and shall define the verification and Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

34



3


59

validation of each stage. Validation is the action taken to ensure that the final product (the output) satisfies specified requirements, whilst verification is the action taken to ensure that what is expected is what happens i.e. it is a comparison of the input with the output. The responsibilities and authorities of personnel related to the design and development shall also be determined. The different D&D groups are coordinated by the laboratory management, which ensures that communications are effective. Slide 35 The laboratory shall identify the inputs 7 PRODUCT REALIZATION that affect the design and development 7.3 Design and Development of the laboratory processes and facilitate 7.3.2 Design and development inputs their effective and efficient perform Functional and performance ance. Inputs are defined from external requirements as well as internal needs and expecta Statutory and regulatory requirements tions. External inputs are drawn from Information from similar design customers, suppliers, users of the labo Other relevant information ratory output, statutory and regulatory requirements, international or national standards, industry codes of practice etc. Internal inputs are drawn from policies and objectives, needs and expectations of people, technological development, past experience etc.

35




Slide 36 The design output of a laboratory 7 PRODUCT REALIZATION process or laboratory service should 7.3 Design and Development include information to enable verifica7.3.3 Design and development output tion and validation to planned Meeting the input requirements requirements. They should meet the Providing information for purchasing, input requirements and provide production and servicing appropriate information to the interested Defining acceptance criteria parties due to use or have a benefit Providing parameters for the safe and proper use of the product from these outputs. Examples of the output of design and development include data demonstrating the comparison of process inputs to process outputs, process specification, testing specifications, acceptance criteria, training requirements etc. 36




60


Slide 37 The design and development processes are systematically reviewed to ascertain that the progress goes as planned. Any problems and opportunities for improvement are identified and necessary action is taken and any changes are controlled.

7 PRODUCT REALIZATION 7.3 Design and Development 7.3.4 Design and development review Systematic reviews at suitable stages Evaluation of D&D results Identification of problems Proposal of necessary action

37


Slide 38



The verification of the D&D process 7 PRODUCT REALIZATION ensures that the D&D output meets the 7.3 Design and Development D&D input requirements. 7.3.5 Design and development The validation of the D&D process is verification the evaluation of the output and 7.3.6 Design and development ensures that the resulting product is validation capable of meeting the requirements 7.3.7 Control of design and development changes for the specified application or intended use. D&D changes shall be identified, reviewed, verified and validated. They should be approved before implementation and their effect on constituent parts and products already delivered should be considered. Records of both verification and validation and review of changes of the design and development and any necessary action shall be maintained. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

38



Slide 39 Materials and services that are purchased by the laboratory should conform to specified requirements and satisfy the defined needs. The laboratory shall define the purchasing requirements and ensure that such requirements are met by the purchased product. The laboratory suppliers should be evaluated for their quality and reliability and should always be monitored regularly. The evaluation of

7 PRODUCT REALIZATION 7.4 Purchasing 7.4.1 Purchasing process Definition of purchase requirements Conformance of purchased product to purchase requirements Control to the supplier and the purchased product Criteria for selection, evaluation and reevaluation of suppliers Evaluation results to be recorded 39



3


61

the laboratory suppliers is based on pre-defined criteria set up by the laboratory. The purchasing processes should consider the quality, cost, performance and delivery of the purchased materials and services, the identification and traceability of the purchased materials, the supplier profile etc. Slide 40 The laboratory shall define the charac7 PRODUCT REALIZATION teristics of the materials, reagents and 7.4 Purchasing instrument to be purchased and evalu7.4.2 Purchasing information ate the ability of the eligible suppliers Definition of the characteristics of the product to supply the required materials and/or to be purchased What is required for the approval of the services. The verification process that purchased product, procedures, processes is, the process to ensure that the and equipment? purchased products conform to the What are the necessary qualifications of personnel? defined requirements shall be defined What are the QMS requirements? and the necessary resources, including personnel, shall be provided. The laboratory suppliers should be considered as part of the laboratory’s quality management system. The type and extend of control applied to the suppliers and the purchased materials shall be dependent upon the effect of the purchased product on the subsequent output. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

40



Slide 41 Based on the verification process already defined, upon receipt of purchased material the laboratory inspects and verifies that the received materials conform to the purchase requirements. When the verification is made at the supplier’s premises there is a need to make arrangements for such verification and for a definition of the method for the release of products.

7 PRODUCT REALIZATION 7.4 Purchasing 7.4.3 Verification of purchased product Inspection of purchased material Purchased product to meet specified purchase requirements Verification at the supplier’s premises Define verification arrangements Define method of product release 41



62


Slide 42 This clause of the standard refers to 7 PRODUCT REALIZATION the whole laboratory activity and 7.5 Production and Service Provision defines the requirements to be carried 7.5.1 Control of production and service out by the laboratory. In order to provision control the laboratory activity there is Production and service provision under controlled conditions such as a need for Availability of information relevant to the information relevant to the the characteristics of the products characteristics of the laboratory Availability of work instructions analysis to be available and … the information relevant for the effective operation of the analytical method to be also available. Moreover, the laboratory operation should be carried out using relevant operating instructions and procedures. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 43

42



7 PRODUCT REALIZATION 7.5 Production and Service Provision

7.5.1 Control of production and service In addition, suitable equipment and provision (contd.) suitable monitoring and measuring Availability of suitable equipment devices should be available so that the Availability and use of monitoring and measuring devices laboratory processes operate effect Monitoring and measurement ively. The procedures for the release Release, delivery and post-delivery of the laboratory product, i.e. the activities acceptance of the laboratory results as well as that for the delivery of such results to the customers, have to be specified and controlled. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

43



Slide 44 7 PRODUCT REALIZATION 7.5 Production and Service Provision

The analytical methods and laboratory 7.5.2 Validation of processes for production and processes shall be validated when the service provision resulting output cannot be verified. Ability of processes to achieve planned results This validation shall demonstrate the Verification of processes by monitoring ability of the methods and processes to or measurement of the resulting output achieve the planned results. This is Validation of processes for production and service provision verified by inspection or measure … ments that the process output (e.g. the laboratory results) is reasonable and within expectations. Analytical methods and laboratory processes shall be validated so that to ensure fitness for the purpose (see chapter 11). Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

44



3


63

Slide 45 The laboratory ensures that the processes that are used for the performance 7 PRODUCT REALIZATION of the analysis operate within defined 7.5 Production and Service Provision limits and that the equipment used for 7.5.2 Validation of processes for production and service provision (contd.) the performance of such processes are Arrangements for processes for production approved and the personnel using this and service provision Criteria for review and approval of the processes equipment are qualified. The operation Approval of equipment and qualification of personnel of the laboratory activity is based on Use of specific methods and procedures the use of specific methods and proce Requirements for records Re-validation dures. Objective evidence that the whole laboratory activity is under control is supported by the relevant records that the laboratory keeps and manages. Processes shall be re-validated from time to time as well as after the occurrence of any changes that might affect the process.

45


Slide 46




The laboratory shall establish a system 7.5.3 Identification and traceability to identify the laboratory results and Identification of the laboratory data, and develop a system to trace product (i.e. the laboratory results) back to the raw data in order to Status of the laboratory product support its findings. For example, the Traceability of laboratory results laboratory reports, the laboratory log back to the raw data books as well as the retention of samples etc. must bear a characteristic number or a well defined code. The status of the laboratory product, i.e. the stage or progress of the work done should be identified. The need for identification and traceability may arise from relevant statutory and regulatory requirements, benchmarking performance, contract requirements etc. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 47


Any property that belongs to the customer and is under the control of the laboratory in order to perform an operation or offer a service to this customer is administered with care. Customer property can include intellectual property. Examples of customer’s

7.5.4 Customer property Protection of the customer’s property that is under the control or is being used by the laboratory Customers to be informed if their product is damaged or unsuitable Records of any damaged or unsuitable property Intellectual property Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

46



47


64


property that is under the control or being used by the laboratory might be the following: reference materials, specifications, drawings, analytical methods or any other intellectual property. Slide 48 The laboratory product should be protected from damage or misuse during internal processing and final delivery to customers.

7 PRODUCT REALIZATION 7.5 Production and Service Provision 7.5.5 Preservation of product Processes for handling, packaging, storage, preservation and delivery of product Prevention of damage, deterioration or misuse Involvement of suppliers to effective protection of purchased materials 48


Slide 49



The devices and analytical instruments 7 PRODUCT REALIZATION that are used in the laboratory to 7.6 Control of Measuring and monitor and measure various paraMonitoring Devices meters during the laboratory activity Determination of the necessary shall be controlled in a way that monitoring and measurements ensures that they are consistent with the Processes to ensure that this activity is carried out monitoring and measurement require Determination of the necessary ments. The laboratory shall determine monitoring and measurement devices … the monitoring and measurements to be undertaken, establish processes to ensure that this activity can be carried out effectively and determine the necessary monitoring and measurement devices. Monitoring and measuring processes in the laboratory include methods and devices for verification and validation of products and processes.

49




3


65

Slide 50 Measuring equipment shall be calibrated or verified at specified intervals or prior to use and adjusted as necessary. The calibration status of each piece of equipment shall be identified and records of the calibration and verification results shall be maintained. When a piece of equipment is found not to conform to requirements, the previous measuring results shall be corrected.

7 PRODUCT REALIZATION 7.6 Control of Measuring and Monitoring Devices Calibration or verification of devices Adjustment of devices Identification of calibration status Protection from damage and deterioration Assessment of the validity of previous results Appropriate action to affected product or equipment Calibration records

50



Slide 51 The primary objective of the quality 8 Measurement, Analysis and management system is the continual Improvement improvement of the management 8.1 General 8.3 Control of nonprocesses and the development of the conforming product 8.2 Monitoring and measurement 8.4 Analysis of data organization via the satisfaction of the 8.2.1 Customer 8.5 Improvement satisfaction interested parties in the organization. 8.5.1 Continual 8.2.2 Internal audit improvement The improvement of the management 8.2.3 Monitoring and 8.5.2 Corrective action measurement of 8.5.3 Preventive action processes of processes comes from the measure 8.2.4 Monitoring and measurement of product ments of the performance and effectiveness of processes and the analysis of the measurement results. This is the last but very important element of the standard and it is analysed below. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

51



Slide 52 The monitoring of the laboratory performance is required to demonstrate that the laboratory product conforms to the specified requirements and that the laboratory activity conforms to the quality management system requirements. Moreover, there is a need and it is a requirement that the laboratory continually improves the effectiveness of the quality management system.

8 MEASUREMENT, ANALYSIS AND IMPROVEMENT 8.1 General

Implementation of processes for monitoring, measurement, analysis and improvement of the laboratory activity and the continual improvement of the effectiveness of the Quality Management System 52



66


Slide 53 The laboratory shall plan and establish processes to listen to the “voice of customer and other interested parties” and cooperate with them in order to anticipate future needs. Such information should be collected, analysed and used for improving the laboratory performance. Measurements of customer satisfaction as well as personnel satisfaction (within the laboratory) are vital for the evaluation of laboratory performance.

8 MEASUREMENT, ANALYSIS AND IMPROVEMENT 8.2 Monitoring and Measurement

8.2.1 Customer satisfaction Meeting customer requirements Processes to collect, analyze and use of customer-related information Customer surveys Measurement of customer satisfaction Customer complaints 53



Slide 54 The laboratory should ensure the establishment of an effective and efficient internal audit process to assess the strengths and weaknesses of the quality management system. The internal audit process provides an independent tool for obtaining objective evidence that the existing requirements have been met, since the internal audit evaluates the effectiveness and efficiency of the laboratory.


8.2.2 Internal audit Internal Audit at planned intervals System conformance to planned arrangements and to the QMS Effective implementation and maintenance of the system 54



Slide 55 The internal audit program takes into consideration the status and importance of processes and areas to be audited. The results from previous audits and the special needs are also taken into account. The internal audit is performed by qualified internal auditors who are members of the organization. However, auditors should not audit their own work.

8 MEASUREMENT, ANALYSIS AND IMPROVEMENT 8.2 Monitoring and Measurement 8.2.2 Internal audit Audit program Status and importance of processes Areas to be audited Results of previous audit Selection of auditors Objectivity and impartiality Not to audit their own work 55



3


67

During the audit process the auditors inspect the effective and efficient implementation of the laboratory processes, the capability of processes, the performance results, the improvement activities and they are also looking for opportunities for improvement. The aim of the internal audit is to determine whether the quality management system conforms to the planned arrangements and if it is effectively implemented. Slide 56 The internal audit procedure is 8 MEASUREMENT, ANALYSIS AND documented and it has to be underIMPROVEMENT 8.2 Monitoring and Measurement stood both by the auditors and those 8.2.2 Internal audit being audited. The objective of the Internal audit procedure internal audit is to contribute to the Elimination of non conformities and improvement of the organization via their causes the elimination Follow up activities of the non-conformities and of the causes of such nonconformities. In response to the internal audit results the laboratory takes improvement action in due time. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

56



Slide 57 The performance of the laboratory 8 MEASUREMENT, ANALYSIS AND processes as well as their output is IMPROVEMENT 8.2 Monitoring and Measurement measured and their ability to conform 8.2.3 Monitoring and measurement to requirements is monitored. When of processes planned results are not achieved, Ability of processes to achieve corrective action shall be taken as planned results appropriate to ensure conformity to the Evaluation of process performance requirements. The decision whether a laboratory process or a laboratory result (the output) conforms to requirements is based on the acceptance criteria that the laboratory defined. Such acceptance criteria could be for example the measurement uncertainty or the response of a measuring instrument. The decision process that is used for ensuring that a laboratory result conforms to the specified requirements considers the analytical methods employed, the parameters to be measured, the equipment used for the analysis etc. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

57



68


Slide 58 The laboratory shall ensure that its results conform to specified requirements. This can be done at appropriate stages of the analysis process. The laboratory product is released and/or a laboratory report is approved by qualified personnel after it has been ensured that they conform to the specified requirements.


8.2.4 Monitoring and measurement of product Ability of product to satisfy the purpose Conformity to the acceptance criteria Qualified persons to release products

58



Slide 59 Non-conformities in the laboratory 8 MEASUREMENT, ANALYSIS AND could be, for example, any results that IMPROVEMENT 8.3 Control of non-conforming products are considered as correct when they Identification of non-conforming products are not, or considered as incorrect Procedure for non-conforming products when they are correct. Non Elimination of non-conformity Release under concession by a relevant conformities in the laboratory could authority or by the customer also be any process output that is not Records for non-conformities and concession Re-verification of corrected products conforming to the input requirements. Completion of planned arrangements before The laboratory should effectively and release efficiently control the nonconformities in order to correct and prevent failures. Non-conformities are corrected and relevant records are collected and analyzed. Such data can provide valuable information for improving the effectiveness and efficiency of the laboratory processes. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

59



Slide 60 The data obtained from measurements are analysed and the subsequent information is used for fact-based decision-making. Such data are used to demonstrate the suitability and effectiveness of the quality management system and to evaluate the continual improvement. The analysis of the data provides information relating to

8 MEASUREMENT, ANALYSIS AND IMPROVEMENT 8.4 Analysis of Data Analysis of data Suitability and effectiveness of the QMS Continual improvement

Customer satisfaction Conformity to product requirements Trends of processes Opportunities for preventive action Performance of suppliers 60



3


69

customer satisfaction and the conformity of processes and products to the requirements. For the analysis of data the laboratory shall employ appropriate statistical techniques. Analysis of the data can help to determine the root cause of existing or potential problems, and therefore indicate the corrective and preventive actions needed for improvement. Slide 61 The laboratory shall continually 8 MEASUREMENT, ANALYSIS AND improve the effectiveness of the quality IMPROVEMENT 8.5 Improvement management system through the use of 8.5.1 Continual improvement the quality policy, quality objectives, Improvement of the effectiveness of the audit results, analysis of data, corrective QMS through the use of the quality policy, quality objectives, audit results, analysis of and preventive actions, and managedata, corrective and preventive action and management review ment review. Improvements can range Small-step improvements from small-step ongoing continual Strategic breakthrough improvements Process for the identification and improvement activities to strategic management of improvement activities breakthrough improvement projects. The laboratory should have a process in place for the identification and management of improvement activities. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

61



Slide 62 Corrective action shall be used as a 8 MEASUREMENT, ANALYSIS AND root for improvement. Sources of IMPROVEMENT 8.5 Improvement information for the consideration of 8.5.2 Corrective action corrective action include customer Elimination of causes of non-conformity Prevention of recurrence complaints, non-conformity reports, Documented procedure internal audit reports, output from Review of non-conformities and customer complaints management review, output from data Causes of non-conformities Need for action analysis, outputs from satisfaction Records of the results of action taken measurements, results of self Reviewing the effectiveness of the corrective action taken assessments etc. Corrective action usually entails significant cost, which is balanced against the impact of the problem being considered before the final decision to proceed with the appropriate corrective action. The elements of the documented procedure are shown in this slide. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

62



70


Slide 63 Preventive action is taken to eliminate the causes of potential nonconformities in order to prevent their occurrence. Corrective action refers to the activities taken to correct something done (e.g. a non-conformity) whilst preventive action refers to the activities so that to avoid something not to be done. The elements of the documented preventive action procedure are shown in this slide.

8 MEASUREMENT, ANALYSIS AND IMPROVEMENT 8.5 Improvement 8.5.3 Preventive action Elimination of causes of potential non-conformity Prevention of occurrences Documented procedure Determination of potential non-conformities and their causes Evaluation of the need for action Implementation of action Records of the results of action taken Reviewing the effectiveness of the preventive action taken Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

63


Slide 64 Summary

ISO 9000 as a quality management ISO 9000 basic requirements Quality management system system sets out the basic requirements Management responsibility Resource management that are necessary for an organization Product realization to administer its management activities Measurement, analysis and improvement The process approach in an effective and efficient manner. Documented quality management system Such requirements are classified in Objective evidence of the conformance of the laboratory activities to the requirements five basic categories as shown in this slide. The basic element of the quality management system is the identification of each management activity as a distinct and well defined process. All quality management system processes have to be identified and the laboratory should establish procedures on how to manage such processes. The quality management system procedures and work instructions should be systematically documented, together with evidence that all of the activities implemented under the quality system fulfilled their requirements. Hadj icostas, E. : I SO 9000 Qu alit y Managem ent System In: W enclawiak, Koch, Hadj icostas (eds.)

64



Slide 65 Where to Get More Information Quality Management Systems – Requirements ISO 9001:2008 Quality Management Systems Guidelines for performance improvements ISO 9004:2000 http://www.iso.org 65



3


71

Bibliography Arvanitoyiannis I, Hadjicostas E (2001) Quality Assurance and Safety Guide for the Food and Drink Industry; CIHEAM/Mediterranean Agronomic Institute of Chania / European Commission MEDA Dux JP (1986) Handbook of Quality Assurance for the Analytical Chemical Laboratory; Van Nostrand Reinhold Friedman FB (1995) Practice Guide to Environmental Management. 6th edition, Environmental Law Institute ISO 9000:2005 Quality Management Systems – Fundamentals and Vocabulary ISO 9001:2008 Quality Management Systems – Requirements ISO 9004:2000 Quality Management Systems – Guidelines for Performance Improvements Johnson PL(1993) ISO 9000 - Meeting the new international standard, McGraw Hill Krajewski JL, Ritzman PL (1999) Operations Management, Strategy and Analysis. 5th edition, Addison-Wesley Pierce FD (1995) Total Quality for safety and health professionals. Government Institutes USA

4

Accreditation or Certification for Laboratories?

Kyriacos C. Tsimillis This presentation is focused on explaining the significance of accreditation and certification for laboratories and illustrates the usefulness of both procedures. The implementation of these procedures in laboratories is described, pointing out their similarities and differences. Reference is made to some publications. The discussion reflects the existing practice. Slide 1 International agreements and regional cooperation e.g. GATT, European Acquis, specify the requirements for the free movement of goods and the elimination of technical barriers to trade, mutual recognition of test results and technical harmonization, in order to meet the needs of the market. The quality concept is being broadened to include additional aspects, tools and procedures.

In Today’s Society… some trends are of importance Free movement of goods Elimination of technical barriers to trade Broadening of quality concept

1

Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)



Slide 2 This is reflected in both legislative requirements and greater competition to meet the demands of society. The access of consumers to more global and detailed information systems, referring to the particular features of products and services provided, as well as increasing consumer awareness, put additional pressure on manufacturers and suppliers.

Quality Issues are… nowadays considered to be of highest importance as a result of increasing awareness of existing needs This is reflected in Legislative requirements and High competition on quality aspects

2





73

74


Slide 3 Some specific needs refer to fields of particular importance, e.g. food quality including all relevant issues; consumer goods governed by the New Approach Directives and relevant harmonised European standards; the protection of the environment and the quality of life as well as the economic concerns of the consumers; dangerous substances and preparations and their impact on human beings, animals and the environment; forensic science.

Specific Needs… exist in some sectors Food Health care services Environmental studies New Approach Directives Dangerous substances Forensic science 3




Slide 4 Conformity assessment can be considered as any action that is undertaken to determine whether a product, a service or a process meets specified requirements. It has been realised that the creation of an international technical language is of high priority; to this end emphasis has been given to enhance cooperation, both on regional and international levels in various fields related to conformity assessment activities.

There is a Need to… create an international technical language to ensure common understanding!

4




Slide 5 Among them, standardization, testing, inspection and quality assurance activities have been developed to cover additional fields of products and services. At the same time great effort is being made worldwide to ensure a harmonised approach both in terminology and the context of various procedures.

As a Result… efficient tools and mechanisms are required Emphasis is given on their worldwide implementation in a harmonised way

5




4


75

Slide 6 Specific tools and mechanisms are being used worldwide to meet the Tools and Mechanisms specified targets. They represent Standardization components of the international tech Laboratory infrastructure nical language referred to above (see Quality management slide 4). Depending on the particular Metrology application, some of these components Accreditation e.g. standardization, quality and environ GLP mental management, accreditation, are being used on a voluntary basis while others are implemented on a compulsory basis within a relevant legislative framework; this is the case with Good Laboratory Practice (GLP) and New Approach Directives. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

6



Slide 7 New Approach Directives, as yet, cover up to 25 products or groups of products specifying the essential requirements with regard to health, safety and environmental issues. The concept of the New Approach in association with Technical Notification promotes aims related to the establishment of the single european market.

Tools and Mechanisms (cont.)

Technical notification Environmental management Modules / notified bodies Harmonised standards Ecolabeling Occupational health and safety 7




Slide 8 All these tools and mechanisms require the appropriate infrastructure to be in place and efficiently operational. Specific tasks are undertaken by competent bodies and institutions in compliance with relevant standards and guidelines, which are issued by regional and international organizations.

The Infrastructure Required… consists of Laboratories Standardization bodies Certification bodies Inspection bodies Accreditation bodies 8




76


Slide 9 How can suppliers and customers worldwide be sure that products and services meet relevant criteria? When they meet standard specifications. How can they be sure that products and services meet such specifications? By conformity assessment. But how can they be sure that conformity assessment activities are reliable? When they comply with the criteria laid down in ISO/IEC standards and guides.

How can We be Sure that… products and services meet the specifications? By “conformity assessment”, i.e. checking that products and services meet the relevant standard´s specifications

9




Slide 10 In official documents of the European Commission it is stated that accreditation should be seen by public authorities, by the accreditors, by the certifiers and by the industry as the highest level of control of conformity assessment activities, from a technical point of view. The diagram illustrates the correlation of various activities and the role of the stakeholders. Accreditation provides the highest level of recognition of activities within conformity assessment.

Demands

Accreditation

Certification Body

Inspection Body

Laboratory

Demands

Market

Product/ Service

Consumer Legislation

Supplier

Requirements

Conformity Assessment

10

Tsimillis, K.C.: Accreditation or Certification for Laboratories? In: Wenclawiak, Koch, Hadjicostas(eds.)

©Springer-Verlag, Berlin Heidelberg 2010 nd

Quality Assurance in Analytical Chemistry –Training and Teaching (2 ed.)

Slide 11 Definitions referring to these activities are given in ISO/IEC Guide 2:2004, EN 45020:2006 and some other normative documents, namely ISO/IEC 9000:2005 and ISO/IEC 17000:2004. Definitions for accreditation and certification given in ISO/IEC Guide 2 are used in the following discussion.

Definitions and Terminology for standardization and related activities are given in various standards ISO/IEC 17000:2004 ISO/IEC Guide 2:2004 EN 45020:2006 ISO/IEC 9000:2005 11




4


77

Slide 12 Accreditation is the third-party attestation related to a conformity assessment body conveying formal demonstration of its competence to carry out specific conformity assessment tasks (ISO 17000). Certification is the procedure by which a third party gives written assurance that a product, process or service conforms to specified requirements.

Following the Definitions… Accreditation refers to competence to carry out specific tasks Certification refers to assurance of conformity to specified requirements

12




Slide 13 Various activities come under conformity assessment; all of them are based on sampling, testing and reporting. First-party testing is carried out by manufacturers and suppliers. Secondparty testing is performed by buyers, users or consumers. Third-party testing is carried out by organizations independent of the above parties.

Testing is Carried out… by laboratories In the private sector In-house Second party Third party

In the public sector Competent authorities 13




Slide 14 Several tens of thousands of standards have been published by national, We Need to Measure! regional and international organizations. If you cannot measure something, it All this accumulated know-how would doesn't exist! remain of limited importance if no Therefore we need means were available for its use as the Methodology basis for measurements; measurement Equipment Personnel and testing are required to assess compliance! The laboratory infrastructure is based on the equipment, the methodology, the premises and the environmental conditions and the personnel involved. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

14



78


Slide 15 The role of laboratories is manifold. The main components are testing and calibration which require measurements and comparisons. This is the area to focus on in the discussion of “accreditation vs. certification”. Other services provided, e.g. development of new methods, consultancy etc., may lead to different conclusions with regard to the relative importance of accreditation and certification.

The Role of Laboratories Drafting of standards Development of new methods Implementation of standards, technical regulations and the legislation Provision of services (testing, calibration, consultancy) 15




Slide 16 The Laboratory Environment

A laboratory requires a constant relationship and close co-operation with all other stakeholders. The laboratory is a living organism within a living and very competitive environment. The links to be established with all stakeholders should be clearly specified to enable the laboratory to function efficiently and meet the needs of its customers (the society through legislation and individuals). The laboratory is supplied with products (reagents, equipment, reference materials), receives services (accreditation, certification, provision of interlaboratory comparison schemes) and cooperates with other laboratories (cooperation in testing, provision of calibration services). Accreditation Body

Legislation

Calibration Laboratories

Laboratories

LABORATORY

-Suppliers -Equipment -Reagents, CRM’s

Certification Body

Customers

16




Slide 17 Laboratories Need…

Why do the laboratories need to demonto demonstrate their technical strate their competence and the reliabilcompetence and reliability ity of their results? Because they need To this end they also need to have policies how to estimate the uncertainty to have competitive advantage and, at of their measurements the same time, comply with legislation, where, more and more, reference is made to the need for reliable results and compliance with specific requirements (Accreditation, Good Laboratory Practice etc.). Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

17



4


79

Slide 18 A series of factors are of decisive importance for the operation and efficiency of a laboratory. They are a mixture of both management and technical competence issues. Guidelines on how to deal with them are included in widely accepted documents.

Laboratories’ Operation is Based on… Quality Management System Methodology Equipment (suitability, calibration, maintenance, conditions) Personnel (competence) Determination of uncertainty 18




Slide 19 A number of documents are very important for laboratories. Their utilisation may vary depending on the specific tasks of the laboratory; they are mainly standards/guides of wide acceptance e.g. from ISO, CEN, ILAC, European directives and EA guidelines, pieces of national and regional legislation etc. They are part of the laboratory’s documentation system.

Basic Documents for Laboratories

ISO/IEC 17025 EA and ILAC Guidelines ISO 9000 ISO 14000 (if applicable) GLP (if applicable) Legislation 19




Slide 20 Further to these, the laboratory community has established very useful links to exchange information and ideas, to submit suggestions and develop policies. Some of the most important fora on European and international level are EA (European cooperation for Accreditation), EURACHEM, EUROLAB, ILAC (International Laboratory Accreditation Cooperation).

To Avoid any Hidden Barriers… to the free movement of goods, services and personnel, conformity assessment activities should be homogeneous and be implemented according to relevant Guides of ISO/IEC and EA/ILAC Guidelines

20




80


Slide 21 Relevant websites are very important sources of information. Those interested Sources of Information can have access to latest inputs and www.european-accreditation.org publications. Another very useful www.eurachem.org contact point is IRMM (the Institute of www.eurolab.org Reference Materials and Measure www.ilac.org ments) of the European Union. www.irmm.jrc.be EUROMED Quality Programme www.euromedquality.org (2004 – 2008) aimed to support Mediterranean countries to upgrade their infrastructure in the perspective of the establishment, by the year 2010, of a Free Trade Zone in the EuroMediterranean region. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

21



Slide 22 Accreditation and Certification

Accreditation and Certification are present both components of the common technical Similarities related to the audit-based infrastructure referred to above (see nature of the procedures and slides 8 and 10). They represent Differences with regard to the tasks and important mechanisms to facilitate free the resulting procedure movement of goods. In a general sense they are dealing with similar issues, mainly because they assess and declare compliance with standards. However they present some major differences, due to the fact that they have different objectives. As a result the procedures to be followed in each case are also different. 22




Slide 23 They are Both Related to…

The main issue that should be taken quality assurance policies considered into account is that certification and of high importance tools in today’s society with regard to the free accreditation serve different tasks. The movement of goods standards used in each case illustrate this difference. The ISO 9000 standards were originally developed to enable manufacturers to demonstrate to all interested parties that they are exercising control over the whole procedure they carry out and over its quality. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

23



4


81

Slide 24 Furthermore it is well known that the ISO 9000 series of standards are applicable in all kinds of activity, both in manufacturing and service sectors; to this end, they can serve their purpose to demonstrate the company’s quality management awareness and organization. This may apply also to laboratories; however it has nothing to do with the particular need of laboratories to demonstrate their technical competence with regard to specific tasks.

However…

this is not enough and does not fit the purpose in the case of laboratories!

24




Slide 25 The first documents dealing with the We Need Something More! competence of laboratories were ISO/IEC Guide 25 and EN 45001 We need tools for the assessment standard. They were issued to provide of the technical competence of laboratories to carry out specified the necessary basis to be used by tasks laboratories and by the bodies that assess their technical performance. In parallel, accreditation bodies undertook additional tasks with regard to the assessment of other activities (certification of products and systems) as specified in other EN 45000 series standards. The ISO/IEC 17025 has replaced EN 45001 (see slide 40), while other standards within EN 45000 series have been replaced by the ones in ISO/IEC 17000 series. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 26 Confusion does exist as a result of different needs as well as different levels of understanding the significance of the terms and the purpose of each procedure. The problem is how to avoid the confusion that exists among laboratories, customers and, more generally, the users of laboratory results.

25



Is there any Confusion… on the use of these two procedures, their significance and their role within conformity assessment activities? If so, why does this happen?

26




82


Slide 27 What about purchasers, both individuals and the ones involved in public procurement, who still mention in invitations for tenders and contracts that the suppliers, including laboratories, should be certified against ISO 9001?

Can Both Activities… be used by laboratories to document their competence and the reliability of their results? Do these two procedures represent equivalent criteria?

27

Tsimill is, K.C.: Accr editation or Certification for Labor atories?

Slide 28 As a result of the differences in nature and objective of the two procedures, differences exist in the way the relevant assessments are carried out. These differences concern the planning and the content of the assessment, the competence of assessors/technical experts, the emphasis given to some basic issues and how the logo is used in each case.




Main Differences Refer to…

The objective and content The documentation Assessors’ competence Procedure of assessment The use of the logo How wide the scope is 28




Slide 29 Technical competence is dealt with only in accreditation and refers both to the methodology used and the personnel involved. In accreditation, validation of methods and expression of uncertainty are of major importance as well as the calibration of equipment and traceability of measurements.

Differences in the Procedure Refer to the following issues Validation of test methods Expression of uncertainty Calibration of equipment Competence of personnel

29




4


83

Slide 30 What about the uncertainty of a measurement? Are clients of the laboratories aware of quality issues and how they can interpret uncertainties given in a test/calibration report? It seems that much more effort should be made to ensure an adequate understanding of such terms.

What about Uncertainty? How educated is the customer to consider properly and make correct use of the expressed uncertainty of measurement?

30




Slide 31 Reliability is a more “customerfriendly” term for uncertainty! Users The Meaning of Uncertainty of test results, including legislators and is not well understood by the customers competent authorities do not always They may not choose a laboratory understand how uncertainty can be which produces results that are used to help them meet their needs. “uncertain” to some extent! Laboratories find it difficult to communicate efficiently with them with regard to this. Based on the existing experience, it seems that not all customers of a laboratory are prepared to pay for a result that is “uncertain to some extent”. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

31



Slide 32 In accreditation the assessment team should consist of assessors/technical experts able to assess all relevant issues including the competence of the staff of the laboratory. This competence needs to be documented by relevant academic/technical qualifications, experience and training as well as successful participation in proficiency testing.

Technical Competence of Personnel Means… Suitable academic qualifications Adequate experience/training Awareness and familiarisation with particular methods and techniques

32




84


Slide 33 The basic question of whether accreditation or certification is appropriate arises when a laboratory is trying to meet the needs of the customers for testing and/or calibration services. Experience shows that the real nature and objectives of ISO 9001 are not always clearly understood by the stakeholders. The situation may be different in each case, depending on the customer.

Quality Means… to meet the customers’ needs How clear are these needs for the customers and how are they expressed in the communication with the laboratories?

33




Slide 34 Different groups of customers may introduce different requirements due to different levels of awareness of quality assurance and laboratory reliability issues. Competent authorities with a responsibility for the implementation of the legislation e.g. health, safety, environmental issues, organizations involved in procurements, the industry and individuals may have different requirements.

Who are the Customers?

Competent authorities Industrial units Purchasers Individuals Other laboratories

34




Slide 35 One of the main reasons for the market demand for certified laboratories refers to the requirement of ISO 9001 for approved suppliers and subcontractors. Certified companies usually require that their potential subcontractors and suppliers are certified themselves. This may also apply for laboratories intended to offer their services to these companies.

ISO 9001 Provides… for suppliers and subcontractors to be included in the approved list Relevant requirements are specified in the quality management system

35




4


85

Slide 36 Certification against ISO 9001 is the usual requirement considered to meet these needs. As a result the industrial units and other enterprises are looking for certified laboratories for testing and calibration services. However, the fulfilment of this requirement does not demonstrate the competence of the laboratory.

The Most Usual Requirement… is ISO 9001 certification This refers also to laboratories that are listed as approved suppliers/ subcontractors

36




Slide 37 A survey was carried out in 1996 by ILAC to evaluate the status of laboratories worldwide with regard to accreditation and certification as well as the needs of their customers and the trends in the market. Up to 500 laboratories responded leading to a series of comments and suggestions.

A Survey was Carried out… by ILAC in 1996 to evaluate the competence of the laboratories, the needs of their customers and market trends

37


Slide 38 Only a small percentage (up to 10%) hold an ISO 9001 certification (or recognition). Big laboratories made more use of their accreditation certificates to demonstrate compliance to ISO 9001, but not very successfully (up to 40%). Accreditation is considered as more effective than certification to consolidate market position and demonstrate technical competence.




According to the Survey… A small percentage of laboratories were certified Big laboratories used accreditation for ISO 9001 compliance Accreditation was preferred to certification to demonstrate technical competence 38




86


Slide 39 The following are among the suggestions made by a high percentage of the Suggestions were then Made … laboratories: for the revision of ISO/IEC Guide 25 and Revision of the then existing tools EN 45001 and harmonization with ISO (ISO/IEC Guide 25 and EN 9001 on management issues 45001) This would facilitate the promotion of mutual recognition of this part of the Harmonization of certification and system accreditation documents with regard to management issues Broadening of accreditation standard to cover management issues for the whole activity of the laboratory Encouraging cooperation and mutual recognition with regard to management issues. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

39



Slide 40 The Standard ISO/IEC 17025:1999

The drafting of an ISO standard on laboratory accreditation to be used Has replaced the former European standard EN 45001 to ensure a instead of EN 45001 was a need for worldwide acceptance of a unique international trade. ISO/IEC Guide 25 document for the assessment of could not be used for this purpose laboratories under accreditation since it was just a guide. However other needs were also reflected in the new standard, namely the ones related to the question “accreditation vs. certification for laboratories” and how to face problems arising from the existing confusion. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

40



Slide 41 1999 Edition of the Standard

The fact that ISO 9001 is a generic Provided for a clarification of the standard for quality management situation applicable to all organizations, no Classified the main requirements in two main categories matter what the specific type of activity, The management issues and implies that a laboratory needs also to The technical competence issues meet quality management requirements in the way specified. The new accreditation standard provides for this in a very clear way, i.e. including relevant provisions. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

41



4


87

Slide 42 ISO/IEC 17025 classifies the main requirements in two main categories, namely the Management Issues (Chapter 4 in the standard) and the Technical Competence Issues (Chapter 5 in the standard). The new standard ISO/IEC 17025 was, in this respect, fully in line with ISO 9001. A detailed correlation with ISO 9001 and 9002 was included in an Annex to the standard.

The Structure of the Standard… enabled a direct correlation with ISO 9001:1994 ISO/IEC 17025 specified management requirements (corresponding to the ones of ISO 9001) and technical requirements in separate chapters

42




Slide 43 The fact that the two standards can be correlated and considered equivalent with respect to the quality management requirements that they specify, facilitates the mutual recognition of systems based on them.

Therefore the Two Standards… could easily be correlated and provide the basis for comparison of the two procedures they refer to

43




Slide 44 The main features and the points mentioned during this presentation are not affected by the revision of ISO in 2000. However this revision introduced the need for a revision of ISO/IEC 17025 as well, soon after its implementation, due to the fact that it refers to the 1994 issue of ISO 9001. Since the 1994 version was not in use any more, there was a revision of ISO/IEC 17025 in 2005.

The Standard ISO 9001:2000 Was the new version of the certification standard As a consequence ISO/IEC 17025 was also revised to be again fully compatible with the new ISO 9001

44




88


Slide 45 This requires some cooperation between accreditation and certification bodies; such cooperation would be appreciated by laboratories since it would provide them with flexibility, lower costs and man-hours and reduce duplication in documentation and assessments.

It is Expected that… in this way an agreement for mutual recognition could be established thus enabling laboratories to avoid duplication in work and additional costs

45




Slide 46 In order for a laboratory to achieve reliability and demonstrate its competence, it needs to proceed with some basic steps, starting with the preparation and implementation of a quality management system. Other steps are as follows…

To Achieve Reliability… a laboratory needs to take some basic steps, starting with the preparation and implementation of a quality management system

46




Slide 47 The diagram illustrates the successive steps to be taken by a laboratory to To Achieve Reliability… establish reliability. The various steps Accreditation refer to different levels of this proceReliability dure. First of all we need to ensure the Competence of personnel Suitability of equipment organizational background to deal with Calibration of equipment Interlaboratory comparisons all management issues. The second Method validation step includes issues related to the Quality Management System (Certification) technical competence while the third step refers to the successful assessment that the target is met. The steps correspond to different levels, e.g. the first step to certification while the third step to accreditation.

47




4


89

Slide 48 The basic starting point for a laboratory trying to establish reliability is the preparation and implementation of a quality management system. The standard to be used is either ISO 9001 where all management issues are addressed or ISO/IEC 17025. This step does not impose the need for certification and does not reflect the competence of the laboratory.

When Taking the First Step… the Laboratory should prepare and implement a Quality Management System as described by either ISO 9001 or ISO/IEC 17025 This step does not impose the need for certification

48




Slide 49 Proper documentation is required for all aspects dealt with so far in order to build confidence in the laboratory’s results. Documentation is necessary to illustrate that every-day operation of the laboratory fully complies with the set requirements.

Further to a Quality Management System…. we need to ensure factors contributing to the reliability of the laboratory Technical competence of personnel Adequacy of infrastructure Fitness of methodology

49




Slide 50 A usual practice for laboratories is to include in the scope of their accreditation a selection of methods they use. The standard provides for certain rules to be followed in reports including results from other methods as well in any relevant declarations. However, the management issues addressed in the quality management system, following ISO/IEC 17025, cover the overall operation of the laboratory.

The Scope of Accreditation Usually includes only few of the methods carried out in the laboratory These methods are the ones for which technical competence is assessed The quality management system covers the overall activity 50




90


Slide 51 In the case of industrial units and other companies certified against ISO 9001 and operating their own laboratory, the latter, as part of the whole system, meets the relevant requirements of ISO 9001.

Laboratories Operating in… certified industrial units have to meet the relevant requirements of ISO 9001 Therefore they may find it easier to go on towards accreditation

51




Slide 52 The accreditation standard specifies that in the case of a laboratory operating as a part of a larger organization performing activities other than testing and/or calibration, appropriate arrangements should be made to avoid conflict of interest and ensure the independence and integrity of the laboratory.

However, in Such a Case… one additional requirement should be considered, i.e. the one referring to the documentation of the independence, in practice, of the laboratory from the parent company

52




Slide 53 The wide acceptance of ISO 9001 and the confidence that specifiers and purchasers have in products and services provided by companies/organizations operating quality management systems according to ISO 9001 cannot be easily ignored. Laboratories have to meet the needs of their customers. Increase in awareness is still necessary.

It should be Clear that… If the need refers only to compliance with quality management issues, certification may be considered adequate Accreditation may also be considered as equivalent with respect to these issues 53




4


91

Slide 54 The main objective is to ensure that the needs are adequately described in It should also be Clear that… each case and that all stakeholders if the need refers to the technical (customers, regulators, competent competence, accreditation of the authorities and other interested parties) laboratory with a detailed description of have a clear understanding of their its scope is the appropriate means to demonstrate it needs and how to meet them. The compliance with quality management issues can be met by certification as well as by accreditation (relevant provisions); the demonstration of technical competence is achieved only through accreditation. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

54



Slide 55 A development of the last years is expected to serve more efficiently the need for clarification. Following the joint ISO-ILAC-IAF Communiqué of June 2005, a statement could be included on accreditation certificates. According to this statement, the accredited laboratory has demonstrated both its technical competence for the defined scope and the operation of a quality management system.

Very Useful Development Statement on accreditation certificate: “This laboratory is accredited in accordance with the recognized International Standard ISO/IEC 17025:2005. This accreditation demonstrates technical competence for a defined scope and the operation of a laboratory quality management system”. (refer joint ISO-ILAC-IAF Communiqué dated 18 June 2005) 55




Slide 56 Both the statement and the joint Communiqué were renewed in January 2009 to reflect the situation with the new version of ISO 9001:2008 (see following slides).

The Statement and Joint Communiqué Were renewed in January 2009 to reflect the revision of ISO 9001:2008

56




92


Slide 57 The consistency in technical competence is interrelated to the compliance with the management system as specified in ISO/IEC 17025:2005, thus illustrating that the standard itself aims at both aspects.

Joint ISO-ILAC-IAF Communiqué (1) “A laboratory´s fulfillment of the requirements of ISO/IEC 17025:2005 means the laboratory meets both the technical competence requirements and management system requirements that are necessary for it to consistently deliver technically competent test results and calibrations… (continued) 57


Slide 58




Furthermore, the equivalence in the Joint ISO-ILAC-IAF Communiqué way both the laboratory accreditation (2) standard and the certification standard … The management system deal with the management system requirements in ISO/IEC 17025:2005 requirements illustrates that an accred(Section 4) are written in language ited laboratory meets, in practice, relevant to laboratory operations and meet the principles of ISO 9001:2000 these requirements as specified in ISO Quality management systems – 9001. After a proposal made via Requirements and are aligned with its Eurachem and EA to ILAC, a similar pertinent requirements”. joint Communiqué was agreed and signed in September 2009 by ILAC, IAF and ISO for medical laboratories against ISO 15189:2007. Tsimill is, K.C.: Accr editation or Certification for Labor atories? In: W enclawiak, Koch, Hadj icostas (eds.)

58



Slide 59

There is Still… much more work to be carried out towards a better understanding and harmonization of the approaches with regard to laboratory work and the use of test and calibration results

59




4


93

Bibliography EUROLAB Report No 3/98 (1998) “Accreditation and/or Certification?”, Workshop in cooperation with EURACHEM, Delft EUROLAB Technical Report 2/2002 “Customer satisfaction with European accreditation bodies” available from http://www.eurolab.org IAF-ILAC-ISO Joint Communiqué on the Management Systems Requirements of ISO/IEC 17025:2005, January 2009, available from http://www.ilac.org IAF-ILAC-ISO Joint Communiqué on the Management Systems Requirements of ISO 15189:2007, September 2009, available from http://www.ilac.org ISO (1998) Development Manual 2: “Conformity assessment”, 2nd edition ISO (2000) “Aligning intentions and implementation in conformity assessment”, ISO Bulletin 31:6 ISO 9001:2008, Quality management systems – Requirements ISO/IEC 17000:2004, Conformity assessment – Vocabulary and general principles ISO/IEC Guide 2:2004 / EN 45020:2006 - Standardization and related activities General vocabulary ISO/IEC 17025:2005 - General requirements for the competence of testing and calibration laboratories ISO 9000:2005 - Quality management systems - Fundamentals and vocabulary Tsimillis K, Michael S (2009) Suggestion to Eurachem and EA for a decision on ISO 15189 and ISO 9001, June 2009

5

Good Laboratory Practice

Evsevios Hadjicostas

Slide 1 The principles of Good Laboratory Practice (GLP) in conjunction with the Good Laboratory Practice principles of Total Quality Manage Good Laboratory Practice (GLP) is a ment (see chapter 6) ensure the quality quality system concerned with the and reliability of the laboratory results, organizational process and the which in turn help to ensure the proconditions under which a study is planned, performed, monitored, tection of the environment and human recorded, archived and reported. health and safety. A step further is the accreditation of laboratories to ISO 17025 (see chapter 2) to perform specified activities. Compliance with the GLP principles covers many aspects of accreditation to ISO 17025. The European Union has adopted the procedures for Good Laboratory Practice of the Organization for the Economic Cooperation and Development (OECD) and calls on member states to take all measures necessary to ensure that laboratories carrying out tests on chemical products comply with the GLP principles. The OECD’s GLP principles are part of the European Commission Directive 2004/10/EC (http://eur-lex.europa.eu). Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

1




95

96


Slide 2 The GLP rules were first introduced in 1976 in the US by the Food and Drug History of GLP Administration (FDA) for non-clinical First in US after irregularities in laboratory studies after some irregularpharmaceutical companies ities in investigations and reports of Other countries followed To increase trust pharmaceutical companies were To be able to export to US revealed. The aim was to create a quality OECD standard for laboratory investigations. First decision in 1981 Binding guidelines in 1989 Based on this all other industrialised countries followed. On the one side because this was necessary to export to US, on the other hand because it was recognised that trust in such investigations could be improved with such regulations. To reduce barriers to trade the Organisation for Economic Cooperation and Development worked on that topic and published its first decision in 1981. To introduce an internationally accepted system in all countries the OECD published “Guides for Compliance Monitoring Procedures for GLP” and “Guidance for the Conduct of Laboratory Inspections and Study Audits” in 1989 which are binding for all OECD member states. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

2



Slide 3 The primary objective of laboratory personnel is to produce quality results that are mutually accepted. The harmonization of the laboratories to the GLP principles will benefit the global economy by the avoidance of the technical barriers to trade and the duplication of analytical determinations. In addition, GLP will improve the quality of life via the protection of human health and the environment.

Why GLP?

Development of quality test data Mutual acceptance of data Avoid duplication of data Avoid technical barriers to trade Protection of human health and the environment 3

Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)


5


97

Slide 4 Scope

The principles of GLP ensure the Non-clinical safety testing of test items generation of high quality and reliable contained in test data related to the safety of indus Pharmaceutical products Pesticide products trial chemicals, pesticides, pharm Cosmetic products aceuticals, food and feed additives, Veterinary drugs cosmetics, veterinary drugs as well as Food and feed additives Industrial chemicals food additives, in the framework of harmonizing testing procedures for the mutual acceptance of data. The purpose of testing these test items is to obtain data on their properties and/or their safety with respect to human health and/or the environment. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

4



Slide 5 The European Commission Directive 2004/9/EC In Europe Directive 2004/9/EC, on the inspection and verification of good EU Member States shall verify the compliance with GLP of any testing laboratory practice, lays down the laboratory within their territory claiming obligation of the Member States to to use GLP in the conduct of tests on designate the authorities responsible chemicals for GLP inspections in their territory. It also comprises reporting and internal market (= mutual acceptance of data) requirements. The directive requires that the OECD Revised Guides for Compliance Monitoring Procedures for GLP and the OECD Guidance for the Conduct of Test Facility Inspections and Study Audits must be followed during laboratory inspections and study audits. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 6

5



Inspection and Audit

The authorities of the EU Member The Annex I of the Directive States shall inspect the laboratory and 2004/9/EC consists of two parts; Part audit the studies in accordance with the A (Guides for compliance monitoring provisions laid down in Annex I of the Directive 2004/9/EC procedures for good laboratory practice) and Part B (Guidance for the conduct of test facility inspections and study audits). The provisions for the inspection and verification of GLP which are contained in Parts A and B are those contained in Annexes I and II respectively of the OECD Council Decision-Recommendation on compliance with principles of good laboratory practice. 6




98


Slide 7 To facilitate the mutual acceptance of Directive 2004/9/EC test data generated for submission to Annex I, Part A Regulatory Authorities of the OECD Guides for compliance monitoring member countries, harmonisation of procedures for good laboratory practice the procedures adopted to monitor GLP compliance, as well as comparability of their quality and rigour, are essential. The aim of this part of the Annex is to provide detailed practical guidance to the Member States on the structure, mechanisms and procedures they should adopt when establishing national GLP compliance monitoring programmes so that these programmes may be internationally acceptable. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

7



Slide 8 Part B of Annex I, provides guidance Directive 2004/9/EC for the conduct of test facility inspecAnnex I, Part B tions and study audits which would be Guidance for the conduct of test facility mutually acceptable to OECD member inspections and study audits countries. It is principally concerned with test facility inspections, an activity which occupies much of the time of GLP inspectors. Test facility inspections are conducted to determine the degree of conformity of test facilities and studies with GLP principles and to determine the integrity of data to assure that resulting data are of adequate quality for assessment and decision-making by national Regulatory Authorities. They result in reports which describe the degree of adherence of a test facility to the GLP principles. Test facility inspections should be conducted on a regular, routine basis to establish and maintain records of the GLP compliance status of test facilities. 8




5


99

Slide 9 OECD Member States developed the The Commission Directive OECD principles of GLP, utilising 2004/10/EC common managerial and scientific The harmonisation of laws, regulations practices and experience from various and administrative provisions relating to national and international sources. The the application of the principles of good purpose of these principles of good laboratory practice and the verification of their applications for tests on laboratory practice is to promote the chemical substances development of quality test data. Comparable quality of test data forms the basis for the mutual acceptance of data among countries. If individual countries can confidently rely on test data developed in other countries, duplicative testing can be avoided, thereby saving time and resources. The application of these principles should help to avoid the creation of technical barriers to trade, and further improve the protection of human health and the environment. GLP principles are explicitly presented below. 9




Slide 10 The GLP Principles

Good Laboratory Practice is a quality system concerned with the organisation of the test facility and the conditions under which non-clinical health and environmental safety studies are planned, performed, monitored, recorded, archived and reported. This is the GLP Decalogue stating the basic principles that the laboratory must follow. Slide 11 A broader term than “the laboratory” is the “test facility”. This includes the persons, premises and operational units that are necessary for the operation of the laboratory. Test sites may be at different locations at which different phases of a study are conducted. Sponsor is the laboratory customer.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Test facility organization and personnel Quality Assurance (QA) program Facilities Apparatus, materials and reagents Test systems Test and reference items Standard Operating Procedures (SOP’s) Performance of the study Reporting of study results Storage and retention of records and materials 10



Terms Concerning the Organization of a Test Facility

Test facility Test site Test facility management Test site management Sponsor Study director Principal investigator Quality assurance program Standard operating procedures Master schedule 11



100


Study director means the individual responsible for the overall conduct of the study. Principle investigator means the individual who acts on behalf of the study director in case of multi site studies. Master schedule means a compilation of information to assist in the assessment of the workload and the tracking of studies at a test facility. Slide 12 Study means an experiment or set of experiments in which a test item is examined. The study plan defines the objectives and experimental design of the study. Test system is the system under study, that is, what we are testing. Usually, we test or analyse a specimen i.e. a sample taken from the test system.

Terms Concerning the Study

Non-clinical health and environmental safety study Short term study Study plan Study plan amendment Study plan deviation Test system Raw data Specimen Experimental starting date Experimental completion date Study initiation date Study completion date 12



Slide 13 Test item is the article that is the subject of a study. The reference item provides the basis for comparison. Batch means a specific quantity of the test or reference item expected to have a uniform character. Vehicle is the carrier of the test item.

Terms Concerning the Test Item Test item: the article that is subject of a study Reference item Batch Vehicle

13


Slide 14 The first principle of the GLP Decalogue is the organization and the personnel of the Test Facility, i.e. the entire laboratory. The responsibilities of the top management and those of the directors within the whole hierarchy are mentioned in detail below.


1. Test Facility Organization and Personnel Test facility management’s responsibilities Study director’s responsibilities Principal investigator’s responsibilities Study personnel’s responsibilities

14



5


101

Slide 15 The laboratory management has the 1. Test Facility Organization and Personnel responsibility to ensure that: Test Facility Management’s Responsibilities The principles of Good Laboratory The management should ensure that The principles of GLP are complied with Practice are complied within its labo A sufficient number of qualified personnel, appropriate facilities, equipment and materials ratory, a Laboratory Policy exists and are available it is communicated and understood by Records of qualifications, job descriptions, training and experience of personnel are the laboratory personnel, a sufficient maintained Personnel understand the functions they are number of qualified personnel, to perform appropriate facilities, equipment, and materials are available in the laboratory and proper training and relevant records of qualifications, training and experience, as well as job descriptions for each professional and technical individual are maintained, all personnel involved in the conduct of the laboratory activity must be knowledgeable about those parts of the principals of Good Laboratory Practice, which are applicable to the activity that they perform. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

15



Slide 16 Technically valid Standard Operating 1. Test Facility Organization and Personnel Procedures (SOPs) have to be Test facility Management’s Responsibilities established and followed. In case of Appropriate and valid SOP’s are established and followed deviations, the impact to the quality is A Quality Assurance Program is in place assessed and appropriate corrective and A Study Director and a Principal preventive action is taken. All SOP Investigator, if needed, is designated Documented approval of the study plan documents have to be controlled and a The study plan is available to quality historical file has to be maintained. assurance personnel The management has to ensure that a Quality Assurance Program is in place and designated personnel perform the program in accordance with the principals of GLP. A documented, properly maintained and approved (by dated signature) Plan of the Laboratory Activities, has to be in place and made available to laboratory and quality assurance personnel. The director of the laboratory is responsible for the overall conduct of the laboratory activities and the approval of the final reports.

16




102


Slide 17 Appropriate characterization has to be 1. Test Facility Organization and Personnel made of reference substances, reagents Test Facility Management’s Responsibilities and other purchased items as well as A document control system is in place Purchased materials meet specified of test samples, solutions and other requirements preparations that are used for the labo Test and reference items are appropriately ratory activity. The supplies must meet characterized Clear lines of communication exist specified requirements appropriate to Computerized systems are suitable for their use. their intended purpose Clear lines of communication have to exist across the whole hierarchy and between the director, laboratory personnel and the quality assurance team. Computerized systems must be suitable for their intended purpose and be validated. All data, including electronic data, must be controlled and properly archived. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

17



Slide 18 The Study Director is the single point of the study control and has the responsibility for the overall performance of the study and the final report. He or she is the delegated individual from the laboratory management to make sure that the laboratory performs under the GLP principles. His or her responsibilities are shown on this and the next slide.

1. Test Facility Organization and Personnel Study Director’s Responsibilities Has the responsibility for the overall performance of the study and the final report Approves the study plan and amendments and communicate them to the QA personnel Ensures that SOPs, study plans and their amendments are available to study personnel Ensures that the SOPs are followed, assess the impact of any deviations and takes appropriate corrective and preventive action 18



Slide 19 1. Test Facility Organization and Personnel

Study director’s responsibilities (continued)

Study Director’s Responsibilities

Ensures that

Raw data are documented and recorded Computerized systems are validated SOPs are followed Deviations are acknowledged Records and data are archived

Sign and date the final report to indicate acceptance of responsibility 19



5


103

Slide 20 The laboratory personnel have their 1. Test Facility Organization and Personnel own responsibilities, i.e. to comply Study Personnel Responsibilities with the instructions given in the rele Knowledge of the GLP principals vant documentation, for recording raw Access to the study plan and appropriate data promptly and accurately and are SOPs Comply with the instructions of the SOPs responsible for the quality of their Record raw data results. The laboratory personnel have Study personnel are responsible for the quality of their data the responsibility to exercise safety Exercise health precautions to minimize risk precautions, to minimize risk to them Ensure the integrity of the study selves and to ensure the integrity of their results. They must be aware of the risk associated with the laboratory work and have knowledge of the appropriate actions to be taken in order to protect all personnel having access to the laboratory (including subcontractors and visitors).

20




Slide 21 2. Quality Assurance Program The laboratory should have a docuGeneral mented Quality Assurance Programme, Documented Quality Assurance (QA) carried out by designated individual(s), Program to assure that the activities performed Designated individuals as members of the QA team directly responsible to the are in compliance with the principles management of GLP. The QA personnel must con QA members not to be involved duct inspections to determine if all of in the conduct of the study being assured the laboratory activities are conducted in accordance with the principals of GLP and defined SOPs. These personnel should not be involved in the laboratory activity being inspected. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

Slide 22

21



2. Quality Assurance Program Responsibilities of the QA Personnel

The role of the quality assurance Access to the updated study plans and SOPs personnel is to inspect the laboratory Documented verification of the compliance of study plan to the GLP principals activity and verify that this activity Inspections to determine compliance of the study with GLP principles. Three types of complies with the GLP principles. inspection They have access to the study plans Study-based inspections Facility-based inspections and Standard Operating Procedures Process-based inspections and all updated versions. QA personnel verify in a documented way the compliance of the study plan with the GLP principles. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

22



104


The inspection is performed according to the quality assurance programme and is based on the audit plan. There can be three types of audit: Test- or Study-based, that is, to inspect thoroughly and meticulously a specific test, test method or study, Facility-based, that is, to inspect the whole facility whether it meets the GLP requirements, Process-based, that is, to inspect the process that the laboratory uses to perform a specific activity. The inspection results are promptly reported in writing and addressed to the toplevel management. Slide 23 As part of the inspection report the QA personnel specifies the inspection types and inspected phases and confirms that the final report reflects the raw data. The inspection results are reported to the management.

2. Quality Assurance Program Responsibilities of the QA Personnel Inspection of the final reports for accurate and full description Report the inspection results to the management Statement

23



Slide 24 The laboratory area should be of suitable size, construction and location to meet the requirements of the laboratory activity and to minimise any disturbance that would interfere with the validity of the results.

3. Facilities Suitable size, construction and location Adequate degree of separation of the different activities Isolation of test systems and individual projects to protect from biological hazards Suitable rooms for the diagnosis, treatment and control of diseases Storage rooms for supplies and equipment

24



5


105

Slide 25 An adequate degree of separation of 3. Facilities the different activities should be pro Separate areas for receipts and storage of vided, i.e. facilities for handling the the test and reference items test samples and reference substances. Separation of test items from test systems Archive facilities for easy retrieval of study Archive facilities should be provided plans, raw data, final reports, samples of test for the secure storage and retrieval of items and specimen Handling and disposal of waste in such a way raw data, final reports etc. not to jeopardize the integrity of the study Samples, reagents, measurement standards and reference materials must be stored so as to ensure their integrity. Handling and storage of wastes should be carried out in such a way as not to jeopardise the integrity of the laboratory activities. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

25



Slide 26 Laboratory apparatus should be 4. Apparatus, Materials and Reagents periodically inspected, cleaned, main Apparatus of appropriate design and tained, and calibrated according to adequate capacity standard operating procedures. Documented inspection, cleaning, maintenance and calibration of apparatus. Records of these activities should be Calibration to be traceable to national or international standards maintained. Calibration should be Apparatus and materials not to interfere with traceable to national or international the test systems Chemicals, reagent and solutions should be standards of measurements. labeled to indicate identity, expiry and specific Chemicals, Reagents, and Solutions storage instructions. should be labelled to indicate identity (with concentration, if appropriate), expiry date and specific storage instructions. Information concerning source, preparation date, the person responsible for the preparation and the stability should be available. The expiry date may be extended on the basis of documented evaluation or analysis. The correct disposal of chemicals, reagents and solvents is a matter of good laboratory practice and should comply with national and/or environmental and/or health & safety regulations. 26




106


Slide 27 Test systems could be physical, chemical or biological. When dealing with biological test systems e.g. animals or plants, special care should be paid to ensure proper conditions for storage, housing and handling. The GLP provisions regarding storage, housing, handling and care of biological test systems are shown in this and the next slide.

5. Test Systems Physical and chemical test systems Appropriate design and adequate capacity of apparatus used for the generation of data Integrity of physical/chemical test systems

Biological test systems Proper conditions for storage, housing, handling and care Isolation of newly received animal and plant test systems until health status is evaluated Humanely destruction of inappropriate test systems Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

27


Slide 28

5. Test Systems Records of source, date of arrival, and arrival conditions of test systems Acclimatization of biological systems to the test environment Proper identification of test systems in their housing or container or when removed Cleaning and sanitization of housings or containers Pest control agents to be documented Avoid interference from past usage of pesticides 28



Slide 29 Receipt, handling, sampling and storage of test and reference items should be clearly defined activities, with welldefined procedures. Also procedures must be provided for the records that are to be kept as evidence of good practice and the identification information on storage containers.

6. Test and Reference Items Receipt, handling, sampling and storage Records for date of receipt, expiry date, quantities received and used in studies etc. Handling, sampling and storage procedures to ensure homogeneity and stability and avoid contamination or mix-up Identification information on storage containers 29



5


107

Slide 30 Characterization of test and reference items.

6. Test and Reference Items Characterization Identification of each test and reference item Code, CAS number, name etc.

Identification of each batch of the test or reference items Batch number, purity, composition, concentration etc.

Cooperation between the sponsor and the test facility Verification of identity of the test item 30



Slide 31 Characterization of test and reference items

6. Test and Reference Items Known stability of test and reference items Stability of the test item in its vehicle (container) Experiments to determine stability in tank mixers used in the field studies Samples for analytical purposes for each batch 31



Slide 32 The laboratory should have written Standard Operating Procedures approved by the Laboratory Director that are intended to ensure the quality and integrity of the data generated by that laboratory. The Laboratory Director has the responsibility to approve revisions to standard operating procedures. The SOPs must be available to the personnel that are involved in the relevant activities as well as to the quality assurance team that performs the audit.

7. Standard Operating Procedures Approved SOPs to ensure the quality and integrity of the laboratory data Immediately available current SOPs relevant to the activities being performed Deviations from SOPs to be acknowledged by the study director 32



108


Slide 33 Standard operating procedures should be available for, but not be limited to, the categories of laboratory activities shown in this and the next slide.

7. Standard Operating Procedures SOPs for Test and reference items Receipt, identification, labeling, handling, sampling, storage

Apparatus Use, maintenance, cleaning, calibration

Computerized systems Validation, operation, maintenance, security, change control, back-up

Materials, reagents and solutions Preparation and labeling Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

33 © Springer-Verlag, Berlin Heidelberg 2010


Slide 34 7. Standard Operating Procedures Record keeping, reporting, storage and retrieval Coding system, data collection, preparation of reports, indexing system, handling of data

Test system Room preparation, environmental room conditions, receipt, transfer, identification etc., test system preparation, observations etc.,

Quality Assurance Procedures Operation of QA personnel 34



Slide 35 The laboratory activities are performed following a well-defined laboratory 8. Performance of the Study plan that gives guidelines to personnel Study plan regarding Written plan, verified for GLP compliance, approved by the study director and by the the methodology to follow, management the expected control limits of the Approval of amendments by dated signatures parameters under study, Deviations to be explained and the reference substances, reagents acknowledged and solutions to be used, the instrumentation to be employed with reference to their performance parameters. Amendments of the study plan are approved and deviations from this are described, explained and acknowledged. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

35



5


109

Slide 36 Content of the study plan 8. Performance of the Study Content of the study plan Identification of the study Title, nat ure and purpose of the study, test item identity, reference item used etc.

Information concerning the sponsor and facility Names and address (sponsor, test facility, study director)

Dates Approval dates of the study plan, estimated starting and completion dates etc.

Reference to test methods Records 36

Slide 37 Each study is given a unique identification and it is conducted in accordance with the study plan. The analyst that performs the tests has the responsibility to record the laboratory data promptly, accurately and legibly. Any changes in the raw data should be made so as not to obscure the previous entry, should indicate the reason for change and should be dated and signed or initialled by the person making the change.



8. Performance of the Study Conduct of the study Identification of each study The study to be conducted in accordance with the study plan Data generated to be recorded directly and accurately Changes in the raw data not to obscure the previous data Identification of electronic data 37



Slide 38 A final report should be prepared after 9. Reporting of Study Results the completion of each laboratory General activity. The final report should be Final report for each study signed and dated by the laboratory Scientists to sign and date their reports Approval by the Study Director director to indicate acceptance of Corrections, additions, amendments to be signed and dated by the study director responsibility for the validity of the Content of the final report data. The extent of compliance with Identification of the study the principles of good laboratory Descriptive title, identification of the test and reference item, purity, stability practice should be indicated. Corrections and additions to a final report should be in the form of amendments and a clear statement of the reasons for the corrections or additions should be made. The final report should include, but not be limited to, the information shown in this and the next slide. Hadj icostas, E.: Good Labor ator y Practice In: W enclawiak, Koch, Hadj icostas (eds.)

38



110


Slide 39 Content of the final report

9. Reporting of Study Results Information on sponsor and test facility Name and addresses of the sponsor, test facility, study director, the scientists involved to the study etc.)

Experimental starting and completion dates A Quality Assurance Program statement Description of materials and test methods Results Including uncertainties, level of significance Evaluation discussion and conclusions

Storage (of samples, reference items, raw data, final reports etc.) 39



Slide 40 A system is to be developed to define the way that records and materials are stored and retained. Records that are stored include, but are not limited to, those on this slide.

10. Storage and Retention of Records and Materials What to retain in archives

The study plan, raw data, samples Inspection data and master schedules Qualification, training experience, job description Maintenance and calibration data Validation data SOPs Environmental, health & safety monitoring records 40



Slide 41 In the absence of a required retention period, the final disposition of materials is documented. When samples are disposed of before expiration date for any reason, this should be justified and documented. Material retained in archives should be indexed so as to facilitate orderly storage and retrieval. Only authorized personnel have access to the archives.

10. Storage and Retention of Records and Materials Retention period to be defined If any study material is disposed of before expiry the reason to be justified and documented Index of materials retained in the archives Controlled access to the archives In case that the laboratory goes out of business the archives are transferred to the relevant sponsor(s) 41



5


111

Slide 42 Good Laboratory Practice is a quality system that is tailored to the needs of Summary the modern laboratories. Its principles GLP v/v ISO 9000 and ISO 17025 are very close to the principles of the Non-clinical health and environmental modern quality management systems safety studies like ISO 9000 and ISO 17025. How Physical and chemical test systems ever, GLP is specific to the non Biological test systems clinical health and environmental OECD safety studies, it covers physical and EU Directive 1999/11/EC chemical test systems, and gives emphasis to biological test systems. It is of utmost importance to note that GLP principles were set out by the Organization for Economic Cooperation and Development (OECD) and after being modified they were adopted by the European Union and are now the Commission Directive 1999/11/EC.

42




Slide 43 Where to Get More Information Commission Directive 2004/9/EC and Commission Directive 2004/10/EC http://eur-lex.europa.eu

http://ec.europa.eu/enterprise/chemicals /legislation/glp/index_en.htm http://www.oecd.org under environment/chemical safety

43



Bibliography: Anderson MA (2000) GLP Quality Audit Manual. Informa Healthcare Anderson MA (2002) GLP Essentials – A Concise Guide to Good Laboratory Practice. Informa Healthcare Arvanitoyiannis I, Hadjicostas E (2001) Quality Assurance and Safety Guide for the Food and Drink Industry. CIHEAM/Mediterranean Agronomic Institute of Chania/European Commission MEDA Crosby NT, Patel I (1995) General Principles of Good Sampling Practice. The Royal Society of Chemistry

112


Dux JP (1986) Handbook of Quality Assurance for the Analytical Chemical Laboratory. Van Nostrand Reinhold Garner WY, Barge MS (1989) Good Laboratory Practices, An Agrochemical Perspective. ACS Symposium Series 369 Haider SI (2002) Pharmaceutical Master Validation Plan: The Ultimate Guide to FDA, GMP, and GLP Compliance. Informa Healthcare Seiler JP (2005) Good Laboratory Practice: The Why and the How, Springer, Berlin

6

Total Quality Management and Cost of Quality

Evsevios Hadjicostas Before we start analysing the philosophy of Total Quality Management it is worthwhile going back to the early days of quality and the quality movement. In fact, the quality concept dates back to the creation of Adam and Eve: “And God saw every thing that he had made, and, behold, it was very good”. (Genesis A 31). It is remarkable that at the end of each day, looking at his creations God was saying, “This is good”. However, at the end of the sixth day, after he finished the creation of human beings, he said, “This is very good”. It is amazing that he did not say, “This is excellent”. This is because excellence is something that we gain after tireless effort. God left room for improvement in order to challenge us and make our life more attractive, which has really happened! In the text that follows we will be referring to the term “organization” and we mean the laboratory. The term “process” refers to any activity in the organization, e.g. the analytical process. Slide 1 The International Quality movement

Before mass production the control of quality was in the hands of the operator. Operator Quality Control Foreman Quality Control This period, of the “operator’s Quality Full-time Inspectors Control” was followed by the “fore Statistical Quality Control man’s Quality Control” period, where Total Quality Control a supervisor was assigned to supervise Total Quality Management the quality of the work of the operators. Then it was the “Full-time inspectors Quality Control” (1920-1930) and the fourth stage was the “Statistical Quality Control” (SQC), first introduced by Deming in Japan in early 1950s. During 1950 Feigenbaum introduced the concept of Total Quality Control (TQC) into western countries, as a management tool to improve product design and quality by reducing operating costs and losses. Kauro Ishikawa, a Japanese chemist, introduced TQC in Japan around 1950-1960 as “a company-wide management tool in order to produce high quality goods and services that give a competitive edge both in the short term and in the future”. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

1




113

114


Slide 2 Total Quality Management (TQM) is a company culture that allows it to Total Quality Management provide quality goods and services at Total Quality Management (TQM) is a the lowest cost in order to achieve philosophy and involves company customers’ satisfaction and, at the practices that aim to harness the human and material resources of an same time, ensure satisfactory busiorganization in the most effective way ness development by continuous imto achieve the objectives of the provements. The definition of TQM (BS 7850) organization shown in this slide is taken from the British Standard 7850. In this chapter we present the management principles of Total Quality Management and the quality improvement methods, as set out in the standards BS 7850 part 1 and part 2 respectively. Furthermore, we introduce the cost of quality and give an outline of the economics of quality, as set out in the BS 6143, Guide to the economics of quality.

2

Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)



Slide 3 For an organization to function effectively and efficiently, it has to identify numerous linked activities. An activity using resources, and managed in order to enable the transformation of inputs into outputs, is considered as a process. Often the output from one process directly forms the input to the next.

What is a Process? Any activity that accepts inputs, adds values to these inputs for customers, and produces outputs for these customers. The customer may be either internal or external to the organization

Controls

Inputs

Process

Outputs

Resources

3




Slide 4 The process of TQM consists of three major activities: Setting the policy and strategy of the organization, effectively and efficiently managing the organization, and seeking continuous improvement.

Typical Process of TQM Policy and strategy of Improvement of the the organization organization Mission Leadership and commitment Divisional objectives

Management of the organization

Working environment Measurement of performance Improvement objectives Improvement plans

Monitor and review

Organization structure Management system Information system Communication 4




6


115

Slide 5 Firstly, the fundamental concepts of Total Quality Management are introPresentation Outline duced. When this is understood the Fundamental Concepts question that arises is “what can we do Implementing Total Quality Management to implement the TQM principles in Quality Improvement our organization?”. At this point we Managing for Quality Improvement Tools for Quality Improvement will understand the need to explain Quality Gurus further the meaning and fundamentals Cost of Quality of the “quality improvement” and how to manage quality improvement. A set of tools for quality improvement has to be installed in our organization so that it is adequately equipped for quality improvement and TQM. To understand TQM in practice a few quality philosophers and their approach to quality will be presented. The ultimate goal of TQM is to give benefits to the organization e.g. by minimizing the cost of quality and maximizing productivity. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

5



Slide 6 The philosophy of the Total Quality Fundamental Concepts Management is applicable to any Commitment to TQM organization, which is customer Commitment to TQM by the highest oriented and committed to quality. level of management Management commitment to Total Promotion of this concept to all levels Quality is essential for the organization and activities of the organization to achieve excellence. Individual involvement Devotion to continuous improvement The commitment to quality must be conveyed to all levels and activities of the organization. Furthermore, management commitment involves every department, function and process in the organization and the active commitment of everyone in the organization to meeting customer needs and seeking continuous improvement. 6




116


Slide 7 All individuals in the organization Fundamental Concepts must be aware of the customers’ needs Customer Satisfaction and be actively committed to satisfy Internal customers ing customers’ requirements. The External customers laboratory’s customer is the raison d’ être of the laboratory and he/she must Customer needs be satisfied and be proud of his/her Customer expectations supplier. An internal customer is a member of the organization, which is part of the process and undertakes the performance of a specific task. The “supplier” to this internal customer is again a member of the organization that transfers his/her product or service to the next member of the chain (his/her customer). To do things “right first time” and on time, and achieve (external) customer satisfaction the internal suppliers and internal customers must always work in perfect coordination. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

7



Slide 8 The resources that are supplied to the Fundamental Concepts laboratory process must be utilized in Quality Losses a way that maximizes the benefit to Ineffective and inefficient utilization of the laboratory and minimizes the loss. human, financial and material resources Quality losses are caused by the failure in processes to utilize most effectively the potential Loss of customer satisfaction of human, financial and material Loss of opportunity to add more value Loss due to waste or misuse of resources in a process. This could be resources due to loss of customer satisfaction, due to loss of the opportunity to add more value to the customer, the organization or the society and/or due to waste or misuse of resources (e.g. peoples’ health, damage to property, process interruption). Opportunities to reduce quality losses steer quality improvement activities. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)



8

6


117

Slide 9 Quality is everyone’s job. The laboraFundamental Concepts tory personnel must have a construcParticipation by All tive role in all laboratory functions and Strengths and abilities of individuals processes. They must operate with a Effective utilization of strengths and team spirit and enhance the synergistic abilities effect of teamwork. All laboratory Communication and teamwork members are links in the chain and nodes in the quality grid. Their strengths and abilities must be fully and effectively utilized. Within this concept the laboratory management recognizes and makes use of the strengths of the laboratory personnel and at the same time recognizes and improves their weak points. It is the responsibility of the chief executive and the laboratory management to cultivate team spirit and make the merits of the human resource known to the laboratory. Communication and teamwork remove organizational and technical barriers and it is essential for everyone to identify and follow up opportunities for improvement. They should be extended through the whole supply chain including suppliers and customers. 9




Slide 10 Measurement is the proof of improvement. Quality improvement cannot be verified if quality is not measured. The very first step for a quality-oriented laboratory is to establish its present situation and quality level. Future comparisons will be referred to this base level. Then, the laboratory must define the parameters that the measurement is based on. Quality is monitored on a systematic basis and the quality results are recorded.

Fundamental Concepts Process Measurements

10




118


Slide 11 Quality improvement is the aim of any modern organization. Improvement needs to be continuous and never ending. The means of improvement can be applied to both the staff and the processes. The degree of improvement achieved can be measured, monitored and controlled.

Fundamental Concepts Continuous Improvement

11




Slide 12 Problems are present in all real situations. These problems provide opportunities for improvement. Problems are there to give the laboratory the opportunity to solve them and to enable laboratories to learn from their problem solving experiences. Provisions for identification and resolution of potential and existing problems on a continuous basis are essential.

Fundamental Concepts Problem Identification

12




Slide 13 The corporate objectives of a laboratory are conveyed to the laboratory members via a well-defined human resource appraisal and development system. The appraisal process is beneficial for both the laboratory management and the laboratorystaff. The goals assigned to the individuals are customer oriented and in line with the corporate goals and the mission of the laboratory.

Fundamental Concepts Alignment of Corporate Objectives and Individual Attitudes Appraisal and development of human resource Quality improvement goals Clear, understandable, specific, measurable, achievable, realistic, time-bound and agreed to by all relevant individuals. Focused on customer satisfaction In line with overall business goals and mission 13




6


119

Slide 14 All laboratory members should accept Fundamental Concepts and recognize the individual’s responPersonal Accountability sibility and authority. This responsibilPersonal Development Responsibilities and authorities for all ity and authority of each individual is individuals defined in job description documents, Job descriptions which are agreed with the interested Appraisal, training and development of parties and communicated to all releindividuals at all levels vant laboratory sectors. Laboratory management must provide for the continuous appraisal, training and development of individuals at all levels in the organization. Training and education is, in fact, part of the remuneration package for all level of employees in the laboratory, as well as for self-employed chemists. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

14



Slide 15 Now that we understand the fundaImplementing Total Quality mental concepts of TQM we proceed Management to the prerequisites needed to Appropriate systems, improvement tools implement TQM. and techniques The laboratory should develop and Application and coordination of the apply a range of appropriate systems, above improvement tools and techniques and Overcome resistance to change coordinate their operation in order to utilize their full potential and achieve improvement. Very often, there is a resistance to change, which requires particular attention to be overcome. It is the responsibility of the management to make people understand that any improvement needs changes to the existing practices and that the benefits from improvement will satisfy all the organization’s members. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

15



120


Slide 16 Resistance to change is overcome and Implementing TQM quality management is achieved Organizational Structure through the ongoing incremental Incremental improvement of processes improvement of the laboratory Review of the appropriateness of the organizational structure: processes. Laboratory management processes The process of improving the Methods of resource allocation Administrative support processes processes within the laboratory creates Human environment a need to review the appropriateness of Training for all laboratory members Laboratory processes and procedures the organizational structure in a way that encourages people to continue their effort towards improvement. Such changes to management structure include changes to the management processes of the laboratory such as reward or payment, recognition and strategic planning, changes to the methods of resource allocation, changes to the administrative support processes such as secretarial, clerical and purchasing building and maintaining a human environment that allows the laboratory personnel to improve quality continually, based on mutual trust and collaboration, enhancing training for all laboratory members and improving laboratory processes and procedures. 16




Slide 17 The organization must consider all Implementing TQM management and operational activities Process Management Concept as processes and measure their effi Process owner and process customer Responsibilities of management and process ciency and effectiveness. The process owners: owner and process customer of each Purpose of each process Customers of each process process as well as management Needs and expectations of customers Needs and expectations of the process owners responsible for the processes must be Performance standards of processes clearly defined. Within each process Measurement of process performance Improvement opportunities the responsibilities of management and process owner must be conveyed to the personnel that perform such processes. The laboratory management is responsible for defining and agreeing the purpose of each one of the laboratory activities and must explain to individuals the relationship of each process to the overall objectives that are rarely known to the technical people.

17




6


121

The purpose of each process and the performance standards for the key activities of the process must be defined and agreed with those that are interested in the results of each such process. The needs and expectations of customers and process owners must be identified. The performance of each process is measured and monitored and opportunities for improvement are sought, the aim being the continual improvement. Slide 18 The performance of all key laboratory Implementing TQM Measurement of Performance functions and processes must be Monitoring the performance of all key assessed based on appropriate performfunctions and processes ance standards. Key attributes: cost, time, flexibility, and quality The performance of functions and Indicators of process efficiency processes should be based on key labour, capital and material utilization, scrap, screening, re-adjustment, waiting time, lost time, attributes and the process efficiency impracticable tolerances,excessive stock etc. Measures of customer satisfaction should be based on well defined Customer surveys, surveys of competing products, routine inspections, customer complaints etc. indicators. Measurement of customer satisfaction (internal and external customers) as well as financial factors should also be considered. This may be based on customer surveys. Such surveys should include, and not limited to laboratory services, customer complaints, reject and reanalysis costs, measures of the time to complete an analysis or delay time to release a batch etc.

18




Slide 19 Planning quality improvement, implementing the plan, analysing the results and re-planning is a continuous cycle (Plan-Do-Check-Act). Interrelated improvement plans are deployed at all levels of the laboratory (corporate, department, process, individual). It is essential to note that the commitment of laboratory personnel is maximized when such personnel is actively involved in the generation and deployment of the improvement plans.

Implementing TQM Improvement Planning Techniques

Planning quality improvement Implementing the plan Analyzing the results ACTION Re-planning

PLAN DO STUDY

Inter-related improvement plans Involvement of staff 19




122


Slide 20 All laboratory personnel, including the Implementing TQM highest levels of management, should Training receive training and education. Such Why training education will enable them to carry out To perform individual process more efficiently and more effectively To be aware of the relationship with other processes their individual processes and functions, To understand the significance of our role to be aware of the relationship of the and the part we play in customer satisfaction and business objectives various laboratory processes, to under To contribute to the continual improvement programs stand the importance of customer satisfaction and the corporate laboratory objectives and to be able to contribute effectively to the continuous improvement programme. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

20



Slide 21 Training programs are important in constructing and maintaining a quality improvement culture in the laboratory. Such programs should be extended to all members of the laboratory so that they are able to understand the quality principles and practices and the appropriate methods and techniques for quality improvement. Subjects for training can include management, technical, process, the use of problem solving tools communication, skills, organization, TQM awareness etc.

Implementing TQM Training Environment for quality improvement Training to all laboratory personnel Quality principles and practices Quality improvement methods

Subjects for training Management, technical, process, problem solving tools, communication, skills, organization, awareness etc 21




6


123

Slide 22 Quality improvement is a continuous activity, aiming to ever higher levels Quality Improvement of process effectiveness and efficiency. Situations requiring improvement Situations requiring improvements High quality costs Customer complaints may arise from different studies and Health and safety considerations surveys, from systematic monitoring Problem solving techniques Identify opportunities for improvement of the laboratory activity, from analyses Apply to all areas of the business of various measurement results and Review priorities of improvement before action statistics etc. A quality driven laboratory is constantly seeking the opportunities for improvement arising when problems are encountered and during problem solving processes. Therefore, problem solving techniques should be applied to all areas of the business and all individuals and groups should be encouraged to use them. For the best use of available resources priorities for improvement should be reviewed before action is taken.

22




Slide 23 The management shall motivate its Quality Improvement members to undertake quality imA Methodology for Quality Improvement provement projects or activities in a Involve the whole organization consistent and disciplined series of Initiate quality improvement projects or steps based on data collection and activities Investigate possible areas for improvement analysis. Establish cause and effect relationship The quality improvement process is Take improvement action initiated and its need, scope and im Confirm the improvement portance are clearly defined. Sustain the gains Investigation of possible areas for improvement increases the understanding of the nature of the process to be improved. The data of the process to be improved are analyzed and a cause and effect relationship is formulated. Alternative proposals for improvement actions are developed and evaluated by the members of the organization involved in such processes. The improvement is confirmed by analyzing more data and the process is introduced into the system.

23




124


Slide 24 -

The quality improvement project or Quality Improvement action starts with the identification Improvement Process of an improvement opportunity Identify which is based on measures of Evaluate quality losses and/or on compari Plan sons against organizations Execute recognized as leaders in a particular Check field. The opportunity for Amend improvement is defined and the process involved is evaluated by analyzing data and facts. The objectives for improvement are introduced. A set of processes is introduced to achieve the improvement in question. Data from such processes are analyzed and evaluated and the causes requiring improvement are identified. The objectives for improvement are also identified. Possible solutions are devised and the preferred one is selected. The implementation of the solution is then planned. The plan is implemented. The results are monitored, reviewed and evaluated. The process is repeated if solution is not achieving its objectives.

24


-

-



Slide 25 The problems encountered in the laboQuality Improvement ratory operations are considered as Problem Solving Process opportunities for improvement. The Identify subjects for improvement problem solving process is an excellent Prioritize tool for people to understand how a Analyze causes of problem process performs and how the laboratory Collect data for analysis operates. Assess alternative solutions for actions The problem solving process starts Select the optimum solution for action with the identification of subjects for improvement. Such subjects are then placed in order of priority. The causes of the problem are identified and analyzed and then, data are collected for analysis and evaluation. Various solutions are assessed and the optimal one is selected.

25




6


125

Slide 26 Another, similar approach to the proQuality Improvement blem solving process, is the one shown Problem Solving Process in this slide. Here, the following ques Identifying the problem tions have to be answered: Describing the problem Which problem should I address? Analyzing the problem If there are several, how do I Planning the solutions choose the most important one? Implementing the solutions How do I accurately and com Monitoring/evaluating the solutions pletely describe the problem? What are the different causes of the problem, and which causes are the important ones to solve right away? What are the possible solutions for solving the problem? How do I make sure the solutions are implemented correctly and effectively? How did the solutions work? What needs to be changed? Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

26



Slide 27 Quality improvement needs first a Managing for Quality Improvement well structured organization, both Organizing for Quality Improvement horizontally and vertically. Responsibilities for quality improvement Within the organizational hierarchy, Within the organizational hierarchy responsibilities for quality improve Management processes Work processes ment include Measurement of the reduction of quality losses Administrative support processes management processes (i.e. pro Building of an environment for quality improvement Within the processes that flow across vision for the policy, the strategy organizational boundaries and the major quality improvement goals, provision of resources, education and training etc.) work processes (i.e. how the various operations are performed), how measurements are done and how quality losses are calculated, how secretarial, budgeting and purchasing processes are performed and how an environment that empowers, enables, and charges all members of the organization to continuously improve quality is built and maintained. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

27



126


Slide 28 Within the processes that flow across organizational boundaries the responsibilities for quality improvement are shown in this slide.

Managing for Quality Improvement Organizing for Quality Improvement Responsibilities for quality improvement Within the organizational hierarchy Within the processes that flow across organizational boundaries Definition of the purpose of each process Communication among departments Identification of internal and external customers Determination of their needs and expectations Searching process improvement opportunities 28

Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y

Slide 29




The laboratory needs to plan for quality Managing for Quality Improvement improvements. Planning for Quality Improvement The planning process should provide Set quality improvement goals for strategic guidance and directions Address the most important quality losses for meeting quality improvement goals Involvement of everyone and implementing quality policy. Inputs from all, from reviews, from suppliers from customers Quality improvement activities that are Focus on newly identified opportunities and employed to achieve the quality where there is insufficient progress Implement quality improvement plans improvement plans should fit in the overall goals and business objectives. The planning process must have inputs from all levels of the laboratory, from reviews of achieved results, and from suppliers and customers. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

29



Slide 30 Quality improvement as a term Managing for Quality Improvement denotes transition from a stage of Measuring Quality Improvement inferior quality to a stage of superior Measure of quality losses quality. This change should always be Associated with customer satisfaction measured in order to prove that the Surveys of current and potential customers Surveys of competing products and services transition to the better stage is success Changes in revenues Inspections ful. The measurements should relate to Customer complaints quality losses associated with Associated with process efficiency Sustained by society customer satisfaction, process efficiencies, and losses sustained by society. This slide shows the basis for measurements associated with customer satisfaction. 30




6


127

Slide 31 The basis of measurements of quality losses associated with process efficiency.

Managing for Quality Improvement Measuring Quality Improvement Measure of quality losses Associated with customer satisfaction Associated with process efficiency Labour, capital and material utilization Unsatisfactory process output Waiting times Delivery performance Size of inventories

Sustained by society 31


Slide 32 The basis of measurements of quality losses sustained by society.




Managing for Quality Improvement Measuring Quality Improvement Measure of quality losses Associated with customer satisfaction Associated with process efficiency Sustained by society Failure to realize human potential (surveys of employee satisfaction) Damage caused by pollution and disposal of waste and depletion of scarce resources 32


Slide 33 Trends displayed by measurements should be interpreted statistically and numerical targets should be established. The measurements are reported and reviewed and trends are evaluated. The cost of measurement is significant and should always be considered.




Managing for Quality Improvement Measuring Quality Improvement

Statistical interpretation of trends Establish and meet numerical targets Measure and track trends Report and review measures Measure the cost of measurement

33




128


Slide 34 A variety of data, either numerical or non-numerical can be gathered in a systematic manner for a clear and objective picture of the facts. This is the data collection form. Such forms are very common in the analytical laboratories and are used to collect and record data and facilitate comparisons.

Tools for Quality Improvement Data Collection Form Establish the specific purpose of collecting this data Identify categories of information Find factors that affect these categories Determine how data will be analysed Multivote to reduce both lists Construct a tabular form Provide a place for information about the origination of the data 34


Slide 35




This organizes a large number of Tools for Quality Improvement (Non-numerical data) opinions, ideas or concerns into groupAffinity Diagram ings based on the natural relationships Start the issue in broad terms that exist among them. It is often used Record individual response in small cards to organize ideas generated by brain Mix the cards and spread them randomly on a large storming. The procedure of applying table an affinity diagram consists of Group related cards together Transfer the information onto recording the individual ideas in small paper outlined by grouping cards and then grouping related cards together. The information from the cards is then transferred onto paper outlined by groupings. The affinity diagram was developed for discovering meaningful groups of ideas within a raw list. In doing so, it is important to let the groupings emerge naturally, using the right side of the brain, rather than according to preordained categories. Maintai nin g a successful C.I. process

Understa nd Customer Require ments

Provide Trainin g

Establish Controls

Getting Manag emen t Committm ent

Improv e Communicatio ns in All Areas

Consult Customer

Know Quality Improv ement Tools

Establish Measur eme nt System

Grant Access to Infor matio n

Interp ret Customer Require ments Correctly in Specs&Desig n

Investigate Other Continuous Improv ement Efforts

Develop an Effective Corrective Action System

Involve Mid dle Mgrs & To p Mgrs. In Steering Committee

Provide Operatio nal Definition of Output

Make Project by Project Improv ement

Identify Customer

Determin e Process Capability Define Process

Establish Consistent Reward System

Employee Involveme nt

Break Down Barriers

Provide Job Security, Free dom t o Fail

Provide Middle Manag ers with Staff Support Provide Clear Program Goals

Provide the Time fo r Middle M gr. To Participa te Create a Steering Committee with Real Power

35




Slide 36 Benchmarking is used to compare an organization’s activity against that of a recognized leader in the market. This will identify opportunities for quality improvement and will lead to competitive advantage in the market place.

Tools for Quality Improvement (Non-numerical data)

Benchmarking Determine what items to benchmark Determine who to benchmark (companies, organizations, competitors, etc.)

Determine benchmark (collect data, surveys, interviews etc.)

Determine the best-in-class for each benchmark item 36




6


129

Slide 37 Brainstorming is an excellent techTools for Quality Improvement (Non-numerical data) nique for tapping the creative thinking Brainstorming of a team quickly to generate, clarify, The rules The steps and evaluate a sizable list of ideas, State the purpose Generation phase Urge people to problems, issues etc. The team leader Clarification phase express ideas Evaluation phase stimulates the team to create numerous Offer one thought at a time ideas irrespective of their quality, Do not criticize ideas Do not discuss ideas which are then clarified and evaluated. Built on other’s ideas During the generation phase the team Record all ideas leader reviews the rules for brainstorming and the team members express their ideas which are then clarified so that everyone understands them. The ideas are evaluated to extract useful information and make appropriate decisions. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

37



Slide 38 A cause and effect diagram (someTools for Quality Improvement (Non-numerical data) times known as the “Ishikawa” or the Cause and Effect Diagram “fishbone diagram”) represents the Define the problem (effect) relationships between a given effect Define the major categories of causes (materials, machines, methods, people, training, and its potential causes. The cause and measurements etc.) effect analysis relates the interactions Construct the diagram Problem Brainstorm possible causes among the factors affecting a process. Analyse each cause The cause and effect diagram is widely Identify the root causes Gather data to verify the root causes used when identifying the effects on a result, including a chemical analysis result. It is used for example in measurement uncertainty to analyse the uncertainty sources. A cause and effect diagram describes a relationship between variables. The undesirable outcome is shown as an effect, and related causes are shown as leading to, or potentially leading to, this effect. Categ. 1

Categ. 2

Cause 1

Cause 2

Categ. 3

Categ. 4

38




130


Slide 39 A flowchart is a pictorial representation Tools for Quality Improvement (Non-numerical data) of the steps in a process and is useful Flowchart for investigating opportunities for List the input to the process or activity improvement by gaining a detailed who supplies and who receives and what is done with this input understanding of how the process List the outputs from each process or activity actually works. From the flowchart, who receives this output and what happens next potential sources of trouble can easily Built the chart using the appropriate symbols and connect all processes be uncovered. In a flowchart there is a Review the chart (correct duplication of processes, rework loops etc.) representation of the inputs and the outputs of a process or activity. The activities and decisions involved in converting an input to an output are shown within the appropriate flowchart symbols. Ordering a Burger Standard Process

Ordering a Burger Improved Process

Approach Counter

Approach Counter

Order Burger

Want Fries?

Order Combo Meal

YE S

Order Fries

YE S

Order Drink

Pay Cashier

NO

Want Drink?

NO

Pay Cashier


39



Slide 40 The tree diagram is used for systematically breaking down a subject into its basic elements. It shows the logical and sequential links between the subjects and the component elements. The core issue, problem or goal is broken into subcategories which are further broken into the component elements and if necessary sub-elements.

Tools for Quality Improvement (Non-numerical data)

Tree Diagram State the core issue problem or goal Define major subcategories of the core Construct the diagram For each subcategory define the component elements and sub-elements Review the diagram to ensure that there are no obvious gaps in sequence or logic

40




Slide 41 A control chart displays statistically Tools for Quality Improvement (Numerical data) determined upper and lower limits Control Charts drawn on either side of a process Select the control chart type average. This chart shows if the Record measurement data on the Y-axis Plot the groups of data collected data are within upper and (e.g. by date) on the X-axis lower limits previously determined Calculate the average and control limits through statistical calculations of raw Mark points of x-bar and control limits on data from earlier trials. the Y-axis The construction of a control chart is Plot observations based on statistical principles and statistical distributions, particularly the normal distribution. When used in conjunction with a manufacturing process, such concentration

upper action limit

upper warning limit

target value

lower warning limits lower action limits

sample-#

1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

17

18

41




6


131

charts can indicate trends and signal when a process is out of control. The centre line of a control chart represents an estimate of the process mean; the upper and lower critical limits are also indicated. The process results are monitored over time and should remain within the control limits; if they do not, an investigation is conducted for the causes and corrective action taken. A control chart helps determine variability so it can be reduced as much as is economically justifiable. In preparing a control chart, the mean upper control limit (UCL) and lower control limit (LCL) of an approved process and its data are calculated. A control chart with mean UCL and LCL with no data points is created; data points are added as they are statistically calculated from the raw data. (See also the chapter on control charts) Slide 42

Frequency

The histogram is a visual representation Tools for Quality Improvement (Numerical data) of the distribution of variable data. Histogram The information is represented by a Collect data series of equal-width columns of Arrange in ascending order Determine the range of the varying heights. Column heights data Determine the width of each represent the number of observations. class interval (column) The natural tendency of data is to fall Put class interval in the X-axis Put frequency scale on the towards the centre of the distribution, Y-axis Draw the height of each with progressively fewer towards the column extremes. After the raw data are collected, they are grouped in value and frequency and plotted in a graphical form. A histogram’s shape shows the nature of the distribution of the data, as well as central tendency (average) and variability. Specification limits can be used to display the capability of the process. 18 16 14 12 10 8 6 4 2 0

1

2

3

4

5

6

7

8

9

10

11

12

Class Series

42


Slide 43



Tools for Quality Improvement (Numerical data)

Pareto Diagram Select the items to be analyzed Causes can be ranked from most to Select the unit of measure for analysis Select the time period to be analyzed least significant. The Pareto diagram List the items in the order of decreasing magnitude is based on the Pareto principle, Construct two vertical axes. The left scale should present the units of which states that just a few of the measures and the right one should be from 0% to 100% causes account for most of the effect. Draw a rectangle above each item Construct the the cumulative frequency Quality experts often refer to the line Identify the most important items principle as the 80-20 rule; that is, 80% of the problems are caused by 20% of the potential sources. By distinguishing the more important causes from the less significant ones the greatest improvement 35

120%

30

100%

25

Frequency

80%

20

60%

15

40%

10

20%

5

0

0%

Causes

few important

many trivial

43




132


will be obtained with the least effort. The Pareto diagram displays, in decreasing order, the relative contribution of each cause (based for example on the number of occurrences, the cost associated with each cause etc.) to the total problem. Slide 44 A scatter diagram shows how two variables are related and is thus used to test for cause and effect relationships. It cannot prove that one variable causes the change in the other, only that a relationship exists and how strong it is. In a scatter diagram, the horizontal (x) axis represents the measurement values of one variable, and the vertical (y) axis represents the measurements of the second variable. Slide 45 W.A. Shewhart, F.W. Taylor, W.E. Deming, J.M. Juran, K. Ishikawa, P.B. Crosby, A.V. Feigenbaum, T.J. Peters, G. Taguchi, T. Ohno, S. Shingo are considered to be the most important persons related to quality in the last 100 years.

Tools for Quality Improvement (Numerical data)

Scatter Diagram Collect paired data Graduate x and y axes Plot the data Label the axes Examine the pattern 44




Quality Gurus

Philip B. Crosby William E. Deming Joseph M. Juran Armand V. Feigenbaum Kauro Ishikawa Tom J. Peters 45




Slide 46 Quality Gurus

Philip B. Crosby was an internationally Philip B. Crosby known quality expert. He is best The four absolutes of Quality Management known for popularizing the Zero Defects concept and the four absolutes 1. Quality equals conformance to requirement 2. Prevention causes quality for quality management that originated 3. Zero defects in the United States at the Martin 4. The measurement of quality is the price of Marietta Corporation where Crosby non-conformance worked during the 1960s. Philip Crosby used a disciplined and highly structured approach, which is not solely product-oriented, but is based entirely on “prevention” and is readily Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

46



6


133

applicable to any enterprise. A new management quality commitment and culture program is achieved through “the four absolutes” of Crosby. Slide 47 A well structured approach, which demonstrates how the culture can be changed and a process improved, is provided through the Crosby’s 14-step quality improvement process.

Quality Gurus Crosby’s 14 Steps for Quality Improvement 1. 2. 3. 4. 5. 6.

7. Zero defects Planning 8. Employee education 9. Zero defects day 10. Goal Setting 11. Error cause removal 12. Recognition 13. Quality Councils 14. Do it all over again

Management Commitment Quality Improvement Team Measurement Cost of Quality Quality Awareness Corrective Action

47




Slide 48 William E. Deming was an American Quality Gurus statistician who was distinguished in William E. Deming Japan and only after 30 years did America and the western countries realize his prophetic philosophy. PLAN Through his philosophy, encoded into ACTION DO his 14 points of management obligations and management commitment, STUDY he removed the major roadblocks to quality improvement and he started the renaissance in quality attitude and promoted a participative management style. Deming is famous for his quality circle which prescribes good management as a cyclical process which follows the order of Plan-Do-Check-Act. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

48



134


Slide 49 Deming’s philosophy is as much about management style and leadership as the practice of quality itself. Through his 14 point of management obligations and management commitment he started the renaissance in quality attitude and promoted a participative management style.

Quality Gurus William Deming’s 14 Points 1. 2. 3. 4. 5. 6.

7. 8. 9. 10. 11. 12.

Institute leadership Drive out fear Breakdown barriers Eliminate exhortation Eliminate targets Permit pride of workmanship 13. Encourage education 14. Top management commitment

Constancy of purpose The new philosophy Cease dependence upon inspection End “Lower tender” contracts Improve every process Institute training on the job

49




Slide 50 Kauro Ishikawa was a Japanese chemist and statistician. The main points of his methodology include involvement of all employees in all stages of decision making, use of quality circles for problem solving and extensive use of statistics and quality control at all stages. He was the inventor of the cause and effect or fish-bone diagram, which is called Ishikawa diagram as well.

Categ. 1

Quality Gurus Kauro Ishikawa

Categ. 2

Cause 1 Cause 2

Categ. 3

Problem

Categ. 4

Involvement of all employees in decision making Quality Circles Extensive use of statistics and Quality Control 50




Slide 51 Joseph M. Juran was one of the most Quality Gurus well known gurus in the quality scene, Joseph M. Juran worldwide. He first visited Japan in Quality Planning 1954 and started conducting seminars Quality Improvement explaining to top managers the role Quality Control they had to play in promoting QC activities. Juran developed the idea of the Quality Trilogy: Quality Planning, Quality Improvement and Quality Control. These three aspects of company-wide strategic quality planning are further broken down in Juran’s “Quality Planning Road Map”, into the following key elements.

Illustration of Quality Trilogy v ia a Control Chart

Quality Planning

Quality Control During Operation

40

Operations Begin

Cost of Quality

Sporadic spike

Original Zone of Quality Control

20

Chronic Waste (an opportunity for improvement)

New Zone of Quality Control

Quality improvement

0

Time

Lessons Learned


51



6


135

Quality Planning Identify who are the customers. Determine the needs of those customers. Translate those needs into our language. Develop a product that can respond to those needs. Optimize the product features so as to meet our needs and customer needs. Quality Improvement Develop a process which is able to produce the product. Optimize the process. Quality Control Prove that the process can produce the product under operating conditions. Transfer the process to operations. Slide 52 Juran stressed that any organization Quality Gurus produces and distributes its products Joseph M. Juran through a series of specialized activities carried out by specialized departments. These activities (actions) are depicted by the spiral of progress in quality. The spiral shows actions necessary before a product or service can be introduced to the market. Each specialized department in the spiral (e.g., customer service, marketing, purchasing) is given the responsibility to carry out its assigned special function. In addition, each specialized department is also assigned a share of the responsibility of carrying out certain company-wide functions such as human relations, finance, and quality. Quality results from the interrelationship of all departments within the spiral. Juran talked about the quality function to describe activities through which the departments around the spiral can attain quality. FURTHER PRODUCT DEVELOPMENT

CUSTOMERS

ETC

MARKETING

PRODUCT DEVELOPMENT

CUSTOMERS

OPERATION S

The Quality Spiral

52




136


Slide 53 Cost of quality is the total cost of ensuring quality in products and serCost of Quality vices (including analytical activities). Measurement of the effect of quality This cost enables the organization to Management of processes measure the effect of quality on Involvement of all individuals to the current practices. Total quality manageprocesses ment requires the management of Process owner processes, not just the outputs. Every Cost of conformance person within the organization Cost of non conformance contributes to and operates within a process, and every process should have an identified process owner who is responsible for the effectiveness of the process. Process cost is the total cost of conformance and cost of non-conformance. Cost of conformance (COC) is the intrinsic cost of providing products or services to declared standards by a given, specified process in a fully effective manner. Cost of non-conformance (CONC) is the cost of wasted time, materials and capacity (resources) associated with a process in the production, dispatch, receipt, and correction of unsatisfactory goods and services. 53




Slide 54 The traditional approach to quality cost modelling categorizes costs as Cost of Quality prevention, appraisal and failure costs. Costs of control Prevention and appraisal costs are the prevention costs costs of assuring quality, and internal The cost of training people, organizing business etc. and external costs are the failure and appraisal costs scrap costs. Added together, these Quality control (analyzing, testing, measuring etc.) produce the total costs. The cost of prevention is that of designing a process, e.g. an analytical method, right in the first place, training laboratory, organizing the laboratory so that work is done efficiently and effectively and improvements can be made all the time. The cost of appraisal in a laboratory is about measuring the laboratory performance, monitoring of the laboratory processes, doing internal quality control, internal and external laboratory audits and so on.

54




6


137

Slide 55 Internal failure cost is the cost when you discover, before release a laboraCost of Quality tory report or an analysis certificate Costs of failure of control internal defect costs that something has gone wrong. Waste, scrap, rework External failure cost is where an Poor design, poor R&D, poor manufacturing work analysis result or certificate reach the external defect costs customer before you discover that Loss of customers, loss of good will, loss of sales something has gone wrong. Lost opportunity cost The lost opportunity cost is the cost when we do not proceed to the routine laboratory activities as a result of other, non productive activities that must take place in the laboratory. In other words, this cost arises when we are dealing with trivial activities that prevent us from doing more important activities. The cost of this lost opportunity is probably the highest of the costs of quality.

55




Slide 56

Costs per Good Unit of Product

The cost for appraisal and prevention Minimizing the Costs of Quality per unit of a good quality product gets higher and higher when the desired defects are minimal, i.e. when we tend to a 100% good quality product. On the other hand the costs of internal and external quality becomes lower and lower when we tend to the production of 100% good product. The minimum cost of quality is found at the lower point of the sum of the two graphs of the cost of appraisal and prevention and that of the internal and external failure costs. A “quality product” in a laboratory could be for example an analysis performed on time with optimal quantities of reagents. Internal and External Failure Costs

Total Quality Costs

Minimum Costs of Quality

Cost of Appraisal and Prev ention

100% Defective

Defect Rate


Optimum Conf ormance Lev el

100% Good

56



138


Slide 57 The idea of the continuous improvement is to reduce or eliminate activities that do not add value and thus are wasteful. In fact, there are many activities in any laboratory that need to be reconsidered. Below are summarized the seven sources of waste that any organization should avoid.

Cost of Quality The Seven Sources of Waste Overproduction Defective products Waiting lines and delays Stocks of intermediaries/semi-finished products Transportation Ineffective procedures Ineffective movements or actions

57


Slide 58




This is the waste coming from the Cost of Quality production of more units than The Seven Sources of Wastes demanded. The optimum number of Overproduction products to be produced must balance the demand, including that in high season periods, the cost of holding the stocks in the warehouse and the cost of setting up the production to produce one lot of the product. In terms of an analytical laboratory, overproduction could be interpreted as any activity that is not necessary for customer service or for adding value to the experience and knowledge of the laboratory. There is no need to analyse too many samples unless we have reasons to do so. Furthermore, there is no need to perform more analyses than necessary. Too many analytical results are a waste. For example, the optimum number of replicates must balance the need for statistical evaluation. 58




6


139

Slide 59 This is the waste coming from the Cost of Quality production of defective products. The The Seven Sources of Wastes manufacturing unit must set up a system to produce the right products Defective products first time in order to avoid the production of defective products, which are either discarded or reprocessed, incurring a significant cost to the organization. A “defective product” for an analytical laboratory is considered any activity or analytical results without any practical use to the laboratory. Hadj icostas, E.: Total Qualit y Management and Cost of Qu alit y In: W enclawiak, Koch, Hadj icostas (eds.)

59



Slide 60 It is a waste of time and money when projects remain too long in waiting lines or there are delays in executing specific tasks. It is the responsibility of the management to design a proper plan in order to distribute the planned actions evenly. Imagine a series of vials in the tray waiting to be processed! Is it necessary for all such samples to be processed? Are they in the correct order? If not this is a waste of time or reagents. Slide 61 Keeping stocks (solvents, materials etc.) enable the laboratory to be responsive to the needs of the customer and in the execution of the analytical work at the right time. However keeping stocks in quantities beyond the minimum can be very costly.

Cost of Quality The Seven Sources of Wastes Waiting lines and delays

60




Cost of Quality The Seven Sources of Wastes Stocks of intermediary/semi-finished products

61




140


Slide 62 Transporting the goods from one point to another within the country in which the organization operates or elsewhere in the world is an activity that requires skills and use of mathematical tools to minimise costs. Transporting the samples from one city to another without sound reasons or transporting the solvents or reagents from one place to another is a “transportation waste”.

Cost of Quality The Seven Sources of Wastes Transportation

62




Slide 63 The procedures that are followed for the optimum performance of a process or action are very important for more effective and efficient operations. Therefore, keep your processes and procedures as unambiguous as you can, but make them as simple as necessary.

Cost of Quality The Seven Sources of Wastes Ineffective procedures

63


Slide 64 All activities within the laboratory must be well structured and organized to avoid ineffective movements or actions. This ineffectiveness can be corrected with the proper layout of instruments and work areas in the laboratory and a proper laboratory activity plan.




Cost of Quality The Seven Sources of Wastes Ineffective movements or actions

64




6


141

Slide 65 Total Quality Management is the applied philosophy that makes busiSummary nesses established as leaders in the Applied philosophy market. The management committed Management commitment to the spirit of TQM ensures that the Achievement of excellence organization does not just survive but Management of change achieves excellence. The modern Continual improvement business environment is subject to Opportunities for improvement rapid changes that take place world Tools for improvement wide and organizations seeking excellence should manage the change effectively and succeed by incremental and continual improvement. Problems that arise in the business activity should be seen as opportunities for improvement and the problem solving process as the route to Ithaca i.e. the route to excellence.

65




Slide 66 Where to Get More Information http://www.philipcrosby.com http://www.isixsigma.com http://www.deming.org/ http://www.juran.com/ BS 7850-1:1992 Total Quality Management, Part 1: Guide to management principles BS 7850-2:1994 Total Quality Management, Part 2: Guide to quality improvement methods BS 6143-1:1992 Guide to the economics of Quality. Part 1: Process cost model BS 6143-2:1990 Guide to the economics of Quality. Part 1: Prevention, appraisal and failure model

66


Bibliography:




Arvanitoyiannis I, Hadjicostas E (2001) Quality Assurance and Safety Guide for the Food and Drink Industry. CIHEAM/Mediterranean Agronomic Institute of Chania / European Commission MEDA BS 6143-1:1992 Guide to the economics of Quality. Part 1: Process cost model BS 6143-2:1990 Guide to the economics of Quality. Part 1: Prevention, appraisal and failure model BS 7850-1:1992 Total Quality Management, Part 1: Guide to management principles BS 7850-2:1994 Total Quality Management, Part 2: Guide to quality improvement methods

142


Friedman FB (1995) Practice Guide to Environmental Management. 6th edition; Environmental Law Institute, Washington Hradesky JL (1987) Productivity and Quality Improvement, A Practice Guide of Implementing Statistical Process Control; McGraw Hill Krajewski JL, Ritzman PL (1999) Operations Management, Strategy and Analysis. 5th edition; Addison-Wesley Mullins E (1994) Introduction to control charts in the analytical laboratory, Analyst 119, 369-375 Pierce FD (1995) Total Quality for safety and health professionals. Government Institutes USA Pyzdek T (1990) Guide to SPC. ASQC Quality Press, Quality publishing

7

Quality Manual

Michael Koch The quality manual is the “heart” of every management system related to quality. Quality assurance in analytical laboratories is most frequently linked with ISO/IEC 17025, which lists the standard requirements for a quality manual. In this chapter examples are used to demonstrate, how these requirements can be met. But, certainly, there are many other ways to do this. Because of the importance of ISO/IEC 17025 it is not possible to deal with this subject without referring to this standard. In the slides all the citations from ISO/IEC 17025 are written in italics. Slide 1 ISO/IEC 17025 is the most important standard for quality assurance in analytical laboratories. All the quality assurance measures must be described in a quality manual.

Quality Manual – Why? ISO/IEC 17025 states the necessity for an accredited laboratory to have a management system related to quality with certain requirements as well as procedures to keep documents under control The quality manual is the keystone of the documentation of a quality management system. 1

Koch, M.: Qualit y Manual

Slide 2 This presentation is structured in two parts. One deals with the contents of a quality manual and the other with the necessary measures for document control.



Quality Manual

Contents Document Control 2

Koch, M.: Qualit y Manual In: W enclawiak, Koch, Hadj icostas (eds.)



143

144


Slide 3 In chapter 4.2.1 of ISO/IEC 17025 the Quality Manual – Contents necessity for a management system ISO/IEC 17025 – 4.2.1 and for documentation of policies, The laboratory shall establish, implement and systems, procedures etc. is stated. It is maintain a management system appropriate to the scope of its activities. important that the system is appropriate The laboratory shall document its policies, systems, programmes, procedures and for the laboratories activities (fit for instructions to the extent necessary to assure the the purpose!). The system and docuquality of the test and/or calibration results. The system’s documentation shall be mentation only make sense, if they communicated to, understood by, available to, and implemented by the appropriate personnel. provide feedback to the personnel. Therefore the documentation has to be communicated to, understood by, available to and implemented by the appropriate personnel. Koch, M.: Qualit y Manual


3



Slide 4 Clause 4.2.2 of ISO/IEC 17025 requires that a quality policy statement be issued by the top management and that the quality system policy and objectives are defined and documented in the quality manual.

Quality Manual – Contents ISO/IEC 17025 – 4.2.2 The laboratory’s management system policies related to quality, including a quality policy statement, shall be defined in a quality manual (however named). The overall objectives shall be established, and shall be reviewed during management review. The quality policy statement shall be issued under the authority of top management. 4



Slide 5 This chapter also lists the necessary contents of a quality manual: the commitment to good professional practice a statement of the standard of service the purpose of the system to ensure quality

Quality Manual – Contents ISO/IEC 17025 – 4.2.2 (followed) It shall include at least the following: the laboratory management’s commitment to good professional practice and to the quality of its testing and calibration in servicing its customers; the management’s statement of the laboratory‘s standard of service; the purpose of the management system related to quality; 5



7

Quality Manual

145

Slide 6 (Continued content): commitment of personnel to implement of the policies and procedures and to act according to the requirements of the system. the management’s commitment to compliance with ISO/IEC 17025 and to continual improvement

Quality Manual – Contents ISO/IEC 17025 – 4.2.2 (followed) a requirement that all personnel concerned with testing and calibration activities within the laboratory familiarize themselves with the quality documentation and implement the policies and procedures in their work; and the laboratory management’s commitment to comply with this International Standard and to continually improve the effectiveness of the management system 6



Slide 7 The quality manual also has to include or has to make reference to all supporting and technical procedures. The quality manual therefore is the central document of the quality management system. The structure of the documentation also has to be outlined in the quality manual.

Quality Manual – Contents ISO/IEC 17025 – 4.2.5 The quality manual shall include or make reference to the supporting procedures including technical procedures. It shall outline the structure of the documentation used in the management system. 7



Slide 8 The roles and responsibilities of the technical and quality management have to be described separately in the quality manual.

Quality Manual – Contents ISO/IEC 17025 – 4.2.6 The roles and responsibilities of technical management and the quality manager, including their responsibility for ensuring compliance with this International Standard, shall be defined in the quality manual.

8



146


Slide 9 As mentioned above the quality policy is one of the most important parts of the quality manual. The whole system should only reflect and realize the quality statements and requirements in the daily work. The policy shall be authorized by the top management, because this statement has to reflect clearly, how crucial quality aspects are in the work of the laboratory.

Quality Policy The quality policy is one of the essential things in the management system. the whole system should only reflect the quality policy in the daily work and put the policy into concrete terms

the policy shall be issued under the authority of the top management It is very important to have a clear statement, how crucial quality is in the work of the laboratory 9



Slide 10 The quality policy has to be very specific for each laboratory, because it depends on the tasks and the clients of the laboratory and eventually on its role in a larger organization. Therefore no recipe can be given for the formulation.

Quality Policy Quality policy is very specific for each laboratory in the framework of its tasks, its role in a larger organization and its relationship to its customers. There is no recipe for the formulation

10



Slide 11 The quality manual should cover all the aspects given in this slide. The statement of independence from influences that may adversely affect the quality of its work is very important and special care has to be taken to identify possible sources of these influences.

Presentation of the Laboratory

This chapter should contain: Address Phone, Fax, e-mail Internet-Website Ownership Year of foundation History Bank account Memberships in associations and organisations

Statement of independence from influences that may adversely affect the quality of the work Cooperation with other laboratories and organizations …

11



7

Quality Manual

147

Slide 12 The organization and laboratory management have to be described in Organization and Management another chapter of the quality manual. Names of persons responsible for This must include the names of commercial management persons responsible for the commercial Names of persons responsible for and for the technical management and technical management their deputies. The qualification of the including a short description of the qualification of the technical manager and technical manager and his/her deputy his deputy must be described in order to show Organization chart that he/she is able to fulfil the necessary requirements. The whole organisation should be described in an organization chart. Koch, M.: Qualit y Manual

12




Slide 13 The organization chart has to reflect the structure of the laboratory. It has to show: who is responsible to whom? and who is who’s boss?

Organization Chart

Dr. J. Bigboss Director Dr. T. Analyst Technical Manager D. Ocument Quality Manager

Dr. T. Oluol Manager Organic Analysis Deputy Technical Manager

Dr. T. Itan Manager Anorganic Analysis

Dr. B. Acter Manager Microbiology

B. Enzene

M. Anganese

E. Coli

P. Esticide

I. Ron

C. Lostridium

P. Henole

C. Opper

A.L.Cohole

B. Ismut 13



Slide 14 The laboratory must have a quality manager. He/she has to be named in the quality manual together with his/her responsibilities. The quality manager must have direct access to the highest level of management responsible for the laboratory in order to have the possibility to indicate on problems that could affect the quality of the work.

Quality Manager The laboratory must have a quality manager (and if possible a deputy) The name and responsibilities/duties have to be stated here The quality manager must have direct access to the highest level of management at which decisions are made on laboratory policy or resources 14



148


Slide 15 The chapter “staff” of the quality manual should state: the number of employees the persons responsible for subdivisions and make reference where information for all technical staff for the items listed is documented

Staff Number of employees Names of persons responsible for subdivisions Reference, where information for all technical staff is documented concerning

Relevant authorizations Competence Educational and professional qualifications Training (in the past and plans for the future) Skills Experience 15



Slide 16 The responsibilities listed here have to be allocated. Especially the responsibility for signing test reports, i.e. the responsibility for the laboratory’s product is very important.

Allocation of Responsibilities

For signing contracts For signing test reports For acquisition For procurement

16



Slide 17 A list of signatures of all the relevant staff has to be included in the quality manual in order to identify them in the documentation of the quality system.

List of Signatures For all relevant staff

17



7

Quality Manual

149

Slide 18 A quality manual does not make any Administration, Access and sense, if the staff do not have access to Review of the Quality Manual it. However, it is imperative that such All staff must have access to the quality access has to be controlled. It has to be manual ensured that all copies in use are current This access must be managed authorized versions. Every authorized All copies must be current versions The quality manual must be regularly copy must therefore be marked as such reviewed and there must be a list with a clear All these things are the duties of the identification of every authorized copy quality manager and where it is located. If the quality manual is changed, it has to be ensured that all authorized copies are changed as well. The quality manual has to be reviewed regularly to see if it is still up to date. The management of access to and review of the quality manual are one of the duties of the quality manager. Koch, M.: Qualit y Manual


18



Slide 19 All operations that are done regularly in the laboratory, especially the analyses, have to be described in standard operation procedures (SOP). It is useful to describe the standard operations in separate documents and to include only a list of all SOP’s in the quality manual.

Standard Operation Procedures There have to be standard operation procedures for all relevant procedures It is useful to have the SOPs in separate documents The quality manual should contain a list of available SOPs 19



Slide 20 The next two slides describe the typical content of a SOP for a test method: a general description to give an overview the identification of any underlying written standard (like ISO, ASTM, BSI, DIN etc.) special requirements for sampling and conservation (or a link to a separate SOP for that)

Standard Operation Procedure – Content - I

General description of the method Underlying standard Sampling and conservation Range of application Interferences Necessary equipment Chemicals (purity, where to buy) Measurement 20



150 -


the range of application for this analysis (e.g. drinking water, waste, sediments, contaminated soils) interferences due to other ingredients necessary equipment and chemicals for the analysis detailed description of the measurement process

Slide 21 SOP content (continued): Standard Operation Procedure – requirements for calibration: e.g. Content - II calibration standards, external/ Calibration internal/standard addition, Evaluation calibration intervals… Control charts Other quality assurance measures evaluation: e.g. use of an internal Use of reference materials standard, … Presentation of results use of control charts (see chapter Limit of detection, limit of quantification, measurement uncertainty 13) Responsibilities use of reference materials (see chapter 14) presentation of results: how many significant digits? which unit? limit of detection, limit of qunatification, measurement uncertainty (see chapter 9 and 12) responsibilities: who is responsible? Who should be called in case of problems?

21





Slide 22 Many of the items mentioned above are described in detail in written standards, but not all of them. The details in this slide are laboratory specific and must therefore be described in a SOP. The extent of a SOP depends also on the qualification of the staff. If this is high, the SOP can be much shorter compared to an SOP for low qualified staff.

Standard Operation Procedure – Standardised Methods A standard method cannot cover the laboratory specific details

Equipment Supplier Trained staff Responsibilities QA measures Limit of detection, ...

These details have to be documented The extent of the SOP depends on the qualification of the staff 22



7

Quality Manual

151

Slide 23 Laboratory internal guidelines for general operations like the calculation of detection limits or the measurement uncertainty should be included in the quality manual or reference made to further documentation.

Other Guidelines If the laboratory has other guidelines, they should be included or referenced in the quality manual For calibration For calculation of detection limits For calculation and construction of control charts For ... 23



Slide 24 Reference materials have to be used, whenever possible. The laboratory has to keep a list of the reference materials in use. This list has to be included or referenced in the quality manual.

Reference Materials The laboratory should keep a list of reference materials used This list has to be in the quality manual Or a note where the RM‘s are listed

24



Slide 25 The accommodation and the environmental conditions in the laboratory must fulfil certain requirements. Such requirements have to be described in the quality manual. Usually the rooms are listed and a floor plan is added.

Accommodation and Environmental Conditions ISO/IEC 17025 contains requirements for accommodation and environmental conditions Their fulfilment must be described in the quality manual Description of the rooms Floor plan 25



152


Slide 26 Each piece of equipment, which is relevant to the tests performed, must have a log book. All changes, calibrations, maintenance etc. must be recorded there. Usually these records are not kept in the quality manual. But a list of all existing log books has to be included. It might be useful to have a guideline on what has to be included in these records.

Equipment There must be records on each item of equipment and its software significant to tests and/or calibration performed Usually on separate documents List of all records (Guideline, what has to be recorded) 26



Slide 27 No equipment lasts forever. Therefore, if it is defective or its operation is out of the specified limits, it has to be marked as “out of service”. There must be regulations in the quality manual on how this should be done, what must be arranged, who has to be informed and who is responsible for looking for a replacement.

Defect and Incorrect Working Test Equipment Equipment that has been shown to be defective or outside specified limits must be taken out of service There must be regulations in the quality manual How the equipment has to be labeled What must be arranged 27



Slide 28 It has to be shown by means of internal audits, that the operation (i.e. the daily work in the laboratory) is in compliance with the quality system. This must be stated in the quality manual: A schedule has to be defined and a standard procedure for internal audits has to be prescribed.

Internal Audits Internal Audits can show that the operation of the laboratory is in compliance with its quality system and with ISO/IEC 17025 Schedule Prescribed procedure Schedule and procedure must be documented in the quality manual 28



7

Quality Manual

153

Slide 29 Regular management reviews are required by ISO/IEC 17025. They can show that the management system and the testing activities are suitable and effective. They have to be planned. The schedule and the procedure have to be documented in the quality manual. Slide 30

Management Review A management review can show the continuing suitability and effectiveness of the management system and of the testing activities Schedule Prescribed procedure Schedule and procedure must be documented in the quality manual 29


Interlaboratory tests are a powerful tool for external quality control (see chapter 15). A laboratory should take part wherever possible. The participation has to be planned. The results and if necessary the corrective actions have to be documented. Procedures have to be accordingly described in the quality manual.


Interlaboratory Tests Participation in interlaboratory test should be a matter of course for each laboratory in its testing field Planning Results Corrective actions 30



Slide 31 The quality manual should also contain procedures on how complaints from clients or from other parties are handled. The laboratory should have a general policy, on how to deal with complaints.

Complaints Policy and procedure for the handling of complaints From clients From other parties

31



154


Slide 32 ISO/IEC 17025 requires a system for document control for all kinds of documents in the laboratory.

Document Control - General ISO/IEC 17025 – 4.3.1 The laboratory shall establish and maintain procedures to control all documents that form part of its management system (internally generated or from external sources), such as

regulations, standards, other normative documents, test and/or calibration methods, as well as drawings, software, specifications, instructions and manuals. 32


Slide 33 What does “document control system” mean? Every document must be clearly identifiable. This includes a unique number and revision status to show if this document has been revised. It could be useful to include the type of document into the number to ease the operation of the system. This is demonstrated on the slide with an SOP as example.




Document Control System Every document must be clearly identified in the control system Together with its revision status This can be done e.g. by a numbering system that includes the revision (e.g. SOP-SA-132-3.1) standard operation procedure

soil analysis

No 132

rev. 3.1

33



Slide 34 ISO/IEC 17025 requires that all documents are reviewed and approved by authorized personal prior to issue. This could be done at the bottom of the first page. A master list of all available documents with their revision status must be established and be available to all personnel to avoid the use of invalid documents

Document Approval and Issue ISO/IEC 17025 – 4.3.2.1 All documents issued to personnel in the laboratory as part of the management system shall be reviewed and approved for use by authorized personnel prior to issue. A master list or an equivalent document control procedure identifying the current revision status and distribution of documents in the management system shall be established and shall be readily available to preclude the use of invalid and/or obsolete documents. Koch, M.: Qualit y Manual In: W enclawiak, Koch, Hadj icostas (eds.)

34


7

Quality Manual

155

Slide 35 The master list has to be included in the quality manual or be referred to there.

Master List There can be e.g. a master list of all valid documents together with their revision status in the quality manual (or in a separate document)

35


Slide 36 In this slide the requirements of ISO/IEC 17025 for the document approval and issue are shown. The next slides will show details following from these requirements.



Document Approval and Issue ISO/IEC 17025 – 4.3.2.2 The procedure(s) adopted shall ensure that: authorized editions of appropriate documents are available at all locations where operations essential to effective functioning of the laboratory are performed; documents are periodically reviewed and, where necessary, revised to ensure that continuing suitability and compliance with applicable requirements; invalid or obsolete documents are promptly removed from all points of issue or use, or otherwise assured against unintended use; obsolete documents retained for either legal or knowledge preservation purposes are suitably marked. 36


Slide 37 Authorized copies (that will automatically be revised if the quality manual changes) should at least be available in the quality manager’s office, in the laboratory manager’s office and to all laboratory staff.



Availability Authorized copies of the quality manual should be available In the quality manager‘s office In the laboratory manager‘s office In the laboratory for all staff

37



156


Slide 38 Obsolete documents have to be removed immediately and all outdated authorized copies must be marked. But they also have to be retained in the archive for knowledge preservation, sometimes also for legal reasons.

Obsolete Documents Have to be removed immediately It must be assured, that they are removed in all authorized copies Obsolete documents must be marked But they have to be retained for Legal purposes Knowledge preservation 38



Slide 39 ISO/IEC 17025 requires a unique identification of all management system documents with the date of issue, revision identification, page numbering, total number of pages on each page and the issuing authority.

Document Approval and Issue ISO/IEC 17025 – 4.3.2.3 Management system documents generated by the laboratory shall be uniquely identified. Such identification shall include the date of issue and/or revision identification, page numbering, the total number of pages or a mark to signify the end of the document, and the issuing authority(ies).

39



Slide 40 Changes of documents have to be reviewed by designated personnel.

Document Changes ISO/IEC 17025 – 4.3.3.1 Changes to documents shall be reviewed and approved by the same function that performed the original review unless specifically designated otherwise. The designated personnel shall have access to pertinent background information upon which to base their review and approval.

40



7

Quality Manual

157

Slide 41 It can be useful to mark altered or new text in changed documents for the reader to see that changes have been made.

Document Changes ISO/IEC 17025 – 4.3.3.2 Where practicable, the altered or new text shall be identified in the document or the appropriate attachments.

41



Slide 42 Amendments of documents must be clearly marked and the revised documents shall be re-issued as soon as possible.

Document Changes ISO/IEC 17025 – 4.3.3.3 If the laboratory’s documentation control system allows for the amendment of documents by hand pending the re-issue of the documents, the procedures and authorities for such amendments shall be defined. Amendments shall be clearly marked, initialled and dated. A revised document shall be formally reissued as soon as practicable. 42



Slide 43 If the documents are maintained in computerized systems there must be procedures to describe how this has to be done and controlled.

Document Changes ISO/IEC 17025 – 4.3.3.4 Procedures shall be established to describe how changes in documents maintained in computerized systems are made and controlled

43



158


Slide 44 To fulfil the requirements of ISO/IEC 17025 it is useful to create a uniform header for quality documents and especially for the quality manual chapters, which e.g. could contain on the first page: Identification of the laboratory Notice that this is a part of the quality manual Number of the chapter Title of the chapter

Header of the Quality Manual At least on the first page of each chapter: Identification of the laboratory A statement that this is a part of the quality manual Number of the chapter Title of the chapter 44





Slide 45 On all pages the header should contain the date of issue, the revision number, the author’s name, the reviewing person, the approval notice, the page number and the total number of pages.

Header of the Quality Manual On each page of each chapter: Date of issue Revision number Name of author Eventually name of person, who checked the content Approval notice Page number Total number of pages of the chapter

45





Slide 46 This slide shows an example for the header of a quality manual chapter.

Example – Top and Bottom of a Quality Manual Page Quality Manual

y tor ora L a b o go L

author:

Quality Policy

checked:

approved:

chapter: 1 revision: 1 page 1 of 3

date of issue:

46



7

Quality Manual

159

Slide 47 The structure of each individual quality manual is a matter for the author. But it is very useful to separate the chapters so that they can be revised individually.

Structure of the Quality Manual It is up to the author of the quality manual to decide about the detailed structure of “his” quality manual. But it is extremely useful to separate it in chapters, which can be revised separately without revising and renumbering the whole manual. 47



Slide 48 If the quality manual is written and used in electronic form, first of all the same requirements have to be met. There must be a system for managing the access rights on the files, a system to ensure that no unauthorized documents is placed on the system, that all withdrawn documents are stored for later information and that all documents are securely backed up.

Quality manual in electronic form The same requirements have to be fulfilled Special emphasis must be put on Unauthorized changes of documents Tracking of withdrawn documents Management of access rights (read/write and read only) Backup 48



Biliography Grimes KR (2003) ISO 9001:2000 a Practical Quality Manual Explained. James Bennett Pty ISO/IEC 17025:2005 – General requirements for the competence of testing and calibration laboratories ISO 9001:2000 – Quality management systems – Requirements Scheutwinkel M., Kindler M (2001) Quality Manual ISO/IEC 17025, MediVision, Berlin

8

Basic Statistics

Michael Koch

Slide 1 Statistics are not “l’art pour l’art”. Statistics are a tool to answer questions. Statistics They can be a very useful tool, Are a tool to answer questions: especially for analysts. Examples of How accurate is the analyses? these questions are: How accurate is How many analyses do I have to make to the analysis? How many analyses do I overcome problems of inhomogeneity or imprecision? have to make to overcome problems of Does the product meet the specification? inhomogeneity or imprecision? Does With what confidence is the limit exceeded? the product meet the specification? What is the confidence that the limit is exceeded? And many more questions in the daily work of chemical analysts can be answered using statistics. Koch, M.: Basi c Stati stics


1



Slide 2 As all analysts know, there are always variations in analytical results. These Analytical Results Vary are due to unavoidable variations Because of unavoidable deviation during during the measurement, variations in measurement the readings of the instruments as well Because of inhomogeneity between the subsamples as variations in the handling of the samples by the analyst. But on the It is very important to differentiate between these two cases other hand there are also variations due Because the measures to be taken can be different to the inhomogeneity of the sample that has to be analysed. The sub-sampling necessary for the analysing process results in different sub-samples. It is very important to differentiate between these two possibilities, because the measures that can be taken to minimize these variations can be totally different.

2

Koch, M.: Basi c Stati stics





161

162


Slide 3 These variations are always present. If there seems to be no variation, the resolution is not high enough. In the first column the presentation of the result is limited to 3 digits and the results are all identical. If one digit is added, some variation can be recognised showing that the results vary between 321.5 and 322.4. With one more digit nearly all results are different.

Variations Are always present If there seems to be none, the resolution is not high enough

322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322

322,3 322,5 322,3 322,2 321,7 321,8 321,7 322,2 321,6 322,4 322,4 321,5 322,4 322,1 322,2 322,5 321,7 321,8 321,9 322,4

322,29 322,49 322,28 322,17 321,67 321,76 321,75 322,17 321,58 322,36 322,40 321,53 322,42 322,05 322,16 322,57 321,73 321,76 321,85 322,41

3

Koch, M.: Basi c Stati stics In: W enclawiak, Koch, Hadj icostas (eds.)


Slide 4 A histogram is used to describe the variability of results. For this purpose the range of possible values for the results is divided in a number of groups. Each group should have the same range. When the measurements are complete, count the number of observations in each group and draw a boxplot of the frequencies vs. the groups.

Histogram For the description of the variability Divide range of possible measurements into a number of groups Count observations in each group Draw a boxplot of the frequencies

4



Slide 5

Histogram 20 18 16 frequency

This diagram shows a histogram of measurements with variations between 45.5 and 51 mg/g of a specific analyte. Most of the measurements are between 48 and 50 mg/g. It can be seen, that it is necessary to have a large number of measurements to be able to draw a histogram.

14 12 10 8 6 4 2 0 45,75 46,25 46,75 47,25 47,75 48,25 48,75 49,25 49,75 50,25 50,75 mg/g

5



8

Basic Statistics

163

Slide 6 If the number of measurements is even larger and the range of values covered by each group is small enough, the histogram changes into a distribution curve. In practice, a distribution curve is a mathematical model for the measurement data.

Distribution If the number of values rises and the groups have a smaller range, the histogram changes into a distribution curve

6





Slide 7 Summing up all the frequencies gives the cumulative distribution. The cumulative distribution curve is the integral of the distribution curve. This curve can be used to find the proportion of the values that fall above or below a certain value. For distribution curves or histograms, which have a maximum, (typical for all analytical measurements), the cumulative distribution curves show the typical S-shape.

Cumulative Distribution The cumulative distribution is obtained by summing up all frequencies It can be used to find the proportion of values that fall above or below a certain value For distributions (or histograms) with a maximum, the cumulative distribution curve shows the typical s-shape 7





Slide 8

Cumulative Distribution 100% 90% 80%

cumulative frequency

The cumulative distribution curve of the above example shows that approximately 50% of the values are below 48.5 and 50 % are above this value. And for example it can also be seen that only about 10 % of the values are below 46,5 mg/g. Also the above mentioned typical S-shape can be seen.

70% 60% 50% 40% 30% 20% 10% 0% 45,75

46,25

46,75

47,25

47,75

48,25

48,75

49,25

49,75

50,25

50,75

mg/g

8



164


Slide 9 It is possible to apply statistics to a set of data, which is complete. This means Population – Sample that all possible data are available, as It is important to know, whether all data (the population) or only a subset (a sample) are for example, the age of all inhabitants known. of a town, where the age of every single Sample Population person is known. In statistics, this set A selection of 1000 All inhabitants of inhabitants of a town a town of data is called a population. On the Any number of Not possible other hand, if only some data are measurements of known (e.g. the age of 1000 selected copper in a soil inhabitants) this is called a sample. If the whole population is known, parameters like the mean can be calculated. If only a sample is known, these parameters have to be estimated. For analytical data, it is only possible to know a sample of all possible measurement results, because the number of these is infinite. Koch, M.: Basi c Stati stics

9




Slide 10 One major task of statistics is to describe the distribution of a set of data. The most important characteristics of a distribution are the location, the dispersion, the skewness and the kurtosis. These are discussed in the following slides.

Distribution Descriptives The data distribution can be described with four characteristics:

Measures of location Measures of dispersion Skewness Kurtosis

10





Slide 11 The most common measure for the location is the arithmetic mean. For random samples from a population this is in most cases the best estimation of the population mean. It is calculated by dividing the sum of all data by the number of data.

Location – Arithmetic Mean Best estimation of the population mean µ for random samples from a population n

x=

∑x

i

i =1

n 11



8

Basic Statistics

165

Slide 12 For the calculation of the median the data have to be sorted by their value. The median is the central value of this series. If the number of data is even, the median is the arithmetic mean of the central values. The median is a so-called robust parameter, because extreme values or outliers do not affect it.

Location – Median Sort data by value Median is the central value of this series The median is robust, i.e. it is not affected by extreme values or outliers

12



Slide 13 The mode is the most frequent value. To calculate the mode it is necessary to have a large number of data with at least partially the same value. Because it is possible to have several data sets with the same value at the same number, it is possible to have more than one mode in the data distribution.

Location – Mode The most frequent value Large number of values necessary It is possible to have two or more modes

13



Slide 14 Besides the above-mentioned measures Location – for the location there are several other Other Means possible parameters. The geometric Geometric mean mean is the arithmetic mean of the th Harmonic Mean logarithms of the data (or the n root Robust Mean (e.g. Huber mean) of the product of all data). The ... harmonic mean is the reciprocal of the mean of the reciprocals of all single values. Methods for robust statistics have been developed that deliver good results (i.e. estimation of the population mean) even with a relatively large number of outliers or with a skewed distribution. For more detailed descriptions of these methods please refer to the relevant textbooks. Koch, M.: Basi c Stati stics


14



166


Slide 15 The most important measure for the dispersion of a data distribution is the variance. The variance of a population (with all possible data being known) is the mean of the squares of the deviations of the individual values from the population mean.

Dispersion – Variance of a Population The mean of the squares of the deviations of the individual values from the population mean n

∑ (x i =1

σ2 =

− μ )2

i

n 15





Slide 16 If not all possible data are known and hence the population mean and the dispersion have to be estimated from a sample, the variance is calculated in a very similar way. In the formula for the variance of a population, the number of data n is replaced by (n-1) and the population mean µ by the arithmetic mean x .

Dispersion – Variance of a Sample Variance of population with (n-1) replacing n and the arithmetic mean of the data (estimated mean) replacing the population mean µ n

s = 2

∑ (x i =1

i

− x) 2

n− 1 16





Slide 17 The standard deviation, for the population as well as that estimated from a sample, is the positive square root of the variance.

Dispersion – Standard Deviation The positive square root of the variance Population

Sample

n

σ =

∑ (x i =1

n

i

− μ )2

n

s=

∑ (x i =1

i

− x) 2

n− 1 17



8

Basic Statistics

167

Slide 18 If means are calculated from samples of the data, they are more closely clustered than the data themselves, because the scattering of the data is eliminated to some extent by calculating the means. The standard deviation of the mean therefore is the standard deviation divided by the square root of the number of measurements used to calculate the mean.

Dispersion – Standard Deviation of the Mean Possible means of a data set are more closely clustered than the data

sdm =

σ n

where n is the number of measurements for the mean

18





Slide 19 In many cases the standard deviation in relation to the mean is more interesting than the absolute value. The relative standard deviation RSD therefore, is the comparison of the standard deviation to the mean and it is often calculated in percent.

Dispersion – Relative Standard Deviation measure of the spread of data compared with the mean

RSD =

s x 19



Slide 20 Randomly selected data from a population are normally symmetrically distributed around the mean value. But in some cases the distribution is unsymmetrical; the distribution is skewed. Data from chemical analyses close to the limit of detection are unavoidably skewed, because negative concentrations are not possible.

Skewness The skewness of a distribution represents the degree of symmetry Analytical data close to the detection limit often are skewed because negative concentrations are not possible

20



168


Slide 21 There is a fourth parameter to describe the characteristics of a distribution, which is the kurtosis. This is the peakedness of the data set. If the data set has a flat peak in the distribution curve it is called platykurtic. If the peak is very sharp it is called leptokurtic. Distributions with peaks in-between are called mesokurtic.

Kurtosis The peakedness of a distribution. Flat Î platykurtic Very peaked Î leptokurtic In between Î mesokurtic

21



Slide 22 The normal distribution and the statistical tools linked with it are the most Normal Distribution - I important statistical tools in analytical First studied in the 18th century by Carl chemistry. The normal distribution Friedrich Gauss was first studied by the German He found that the distribution of errors could be closely approximated by a curve called the mathematician Carl Friedrich Gauss as „normal curve of errors“ a curve for the distributions of errors. In putting his picture, his formula and the curve on the former 10 DM bill the German government recognized the importance of his studies. The discussion of other distributions that are important in some circumstances goes beyond the scope of this book and the reader is referred to statistics textbooks to find more details. 22





Slide 23 The curve of the normal distribution is bell shaped and is completely determined by only two parameters, the central value µ and the standard deviation σ.

Normal Distribution - II Bell shaped Completely determined by µ and σ

y=

( x−μ ) 1 2 e 2σ σ 2π

2

23



8

Basic Statistics

169

Slide 24 The normal distribution has some properties that are very important in understanding statistical results. The curve is symmetrical about the central value µ. 68,27% of the values lie within µ ± 1σ, 95,45% within µ ± 2σ and 99,73% within µ ± 3σ.

Normal Distribution – Important Properties The curve is symmetrical about µ

The greater the value of σ the greater the spread of the curve Approximately 68% (68,27% ) of the data lie wit hin µ±1σ Approximately 95 % (95, 45%) of the data lie within µ±2σ Approximately 99,7 % (99,73%) of the data lie within µ±3σ

y=

( x−μ ) 1 2 e 2σ σ 2π

2

24



Slide 25 For many purposes in analytical chemistry the normal distribution is a very useful model. The area under the normal curve can be divided in various sections characterized by the arithmetic mean and a multiple of the standard deviation. These areas can then be interpreted as proportions of observations falling within ranges defined by specific probabilities.

Normal Distribution – a Useful Model With the mean and the standard deviation area under the curve can be defined These areas can be interpreted as proportions of observations falling within these ranges defined by µ and σ

25



Slide 26 If one has a specific problem, which can be converted into a statistical question, it is important to know if the question is one-tailed or two-tailed. Typically one-tailed are questions for limits, such as: “Is the limit exceeded or not?” (e.g. alcohol in blood). If we want to know whether a measured value lies within a certain range this is a typically two-tailed question. The value could be too low or too high.

One-tailed / Two-tailed Questions One-tailed E.g. a limit for the specification of a product It is only of interest, whether a certain limit is exceeded or not

Two-tailed E.g. the analysis of a reference material We want to know, whether a measured value lies within or outside the certified value ± a certain range 26



170


Slide 27 In this figure the one-sided probabilities are shown for a couple of multiples of σ. The probability that a value is lower than µ + σ is 84.1%. Or, the other way round: With a probability of 95%, the value is lower than µ + 1,64σ and with a probability of 5% it is higher than µ + 1,64σ. Please note: The low probability that a value may be e.g. below µ - 3σ does not matter in this case. The only question is: What is the probability that the value exceeds µ + kσ?

One-sided Probabilities Less than µ + kσ, P() k 1 1.64 1.96 2 3

μ

P() 0.159 0.050 0.025 0.023 0.002

μ + kσ 27





Slide 28 For two-sided probabilities we get the well-known values of a probability of Two-sided Probabilities 68.3% for a value being within the range of µ ± σ, 95.4% for the range µ ± 2σ and 99.7% for the range µ ± 3σ. In analytical chemistry the 90 and 95% values very often are used. These correspond to k-values of 1.64 and 1.96 µ-kσ µ µ+kσ respectively. Note: If a value is given together with its standard deviation (or in most cases an estimation of this value), the probability for a single measurement lying within ± one standard deviation is only 68.3%.

Area w ithin the range µ ± kσ, P(in) Area outside the range µ ± kσ, P(out) k 1 1.64 1.96 2 3

P( in) 0.683 0.900 0.950 0.954 0.997


P( out) 0.317 0.100 0.050 0.046 0.003

28




Slide 29 Population / Sample

Small random samples of results from a normal distribution may not look normal at first sight E.g. samples from a population of 996 data all e 996 values sample sample of of249 100 10 20 50 vvalues alues sampl of 498 valu es

Population: µ=100, σ=19,75

45 3,5 12 6 8 25

Sample size mean

frequency frequency frequency

40

7 10 53 35 20 6 2,5 30 48 5 15 2 25 36 4 20 1,5 10 3 24 15 21 10 15 2 0,5 15

1

11333 6888

11444 4666 11555 2444

1

value value value

11233 38000

1 110066 46

11111 24444 1122 2022

455580 00 5555688 8 6666466 6 774 7244 888022 2 9890 9800 9 998688

000

444222

It may be very difficult to see from small random samples if a population is normally distributed. In this slide an example is given with samples from a population of 996 data. The population mean is 100 and the standard deviation is 19.75. First, 10 data are randomly sampled (about 1% of the data) resulting in an estimation for the mean of

10 20 50 100 249 498

99.6 101.8 97.76 96.52 98.63 97.81

s 20.48 18.14 19.13 20.14 20.10 20.49 29



8

Basic Statistics

171

99.6 and an estimated standard deviation of 20.48. This sample does not look as though it is normally distributed. Even when we randomly take 50% of the values, the estimated values for the mean and the standard deviation are not much closer to the true value although the data does look well distributed. Slide 30 The result of a chemical analysis is never a single value, but a range in which the true value is supposed to lie with a given confidence. This range is called confidence interval or confidence limits. The greater the confidence required the larger the interval will be. Slide 31

Confidence Limits / Intervals The confidence limits describe the range within which we expect with given confidence the true value to lie.

30




If the population standard deviation is known and the mean is estimated from one measurement, for a confidence level of 95 % the true value will lie in the range of x ± 1.96 ⋅ σ . If the mean is estimated from n measurements the range has to be divided by n .


Confidence Limits for the Population Mean If the population standard deviation σ and the estimated mean are known: CL for the population mean, estimated from n measurements on a confidence level of 95%

CL = x ± 196 . ⋅

σ n

31



Slide 32 Normally the population standard deviation σ is not known, and has to be estimated from a sample standard deviation s. This will add an additional uncertainty and therefore will enlarge the confidence interval. This is reflected by using the Student-tdistribution instead of the normal distribution. The t value in the formula can be found in tables for the required confidence limit and n-1 degrees of freedom.

Confidence Limits for the Population Mean If the standard deviation has to be estimated from a sample standard deviation s (this is normally the case): Additional uncertainty Î use of Student t distribution Where t is the two-tailed

CL = x ± t ⋅

s n

tabulated value for (n-1) degrees of freedom and the requested confidence limit 32



172


Slide 33 The table on this slide is an example for such t-values. In the first two rows are the confidence levels for one-tailed (1T) and two-tailed (2T) questions. The first column shows the degrees of freedom, which is obtained from the number of measurements. Tables with t-values might be found in all statistics textbooks and relevant standards.

t-values Critical valu es for the Student t-Test d.o.f. \ 1T d.o.f. \ 2T 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

60% 20% 0,3249 0,2887 0,2767 0,2707 0,2672 0,2648 0,2632 0,2619 0,2610 0,2602 0,2596 0,2590 0,2586 0,2582 0,2579 0,2576 0,2573 0,2571 0,2569 0,2567

75% 50% 1,000 0,8165 0,7649 0,7407 0,7267 0,7176 0,7111 0,7064 0,7027 0,6998 0,6974 0,6955 0,6938 0,6924 0,6912 0,6901 0,6892 0,6884 0,6876 0,6870

80% 60% 1,376 1,061 0,9785 0,9410 0,9195 0,9057 0,8960 0,8889 0,8834 0,8791 0,8755 0,8726 0,8702 0,8681 0,8662 0,8647 0,8633 0,8620 0,8610 0,8600

85% 70% 1,963 1,386 1,250 1,190 1,156 1,134 1,119 1,108 1,100 1,093 1,088 1,083 1,079 1,079 1,074 1,071 1,069 1,067 1,066 1,064

90% 80% 3,078 1,886 1,638 1,533 1,476 1,440 1,415 1,397 1,383 1,372 1,363 1,356 1,350 1,345 1,341 1,337 1,333 1,330 1,328 1,325

95% 90% 6,314 2,920 2,353 2,132 2,015 1,943 1,895 1,860 1,833 1,812 1,796 1,782 1,771 1,761 1,753 1,746 1,740 1,734 1,729 1,725

97,50% 95% 12,71 4,303 3,182 2,776 2,571 2,447 2,365 2,306 2,262 2,228 2,201 2,179 2,160 2,145 2,131 2,120 2,110 2,101 2,093 2,086

99% 98% 31,82 6,965 4,541 3,747 3,365 3,143 2,998 2,896 2,821 2,764 2,718 2,681 2,650 2,624 2,602 2,583 2,567 2,552 2,539 2,528

99,50% 99% 63,66 9,925 5,841 4,604 4,032 3,707 3,499 3,355 3,250 3,169 3,106 3,055 3,012 2,977 2,947 2,921 2,898 2,878 2,861 2,845

99,90% 99,80% 318,3 22,33 10,21 7,173 5,893 5,208 4,785 4,501 4,297 4,144 4,025 3,930 3,852 3,787 3,733 3,686 3,646 3,610 3,579 3,552

99,95% 99,90% 636,6 31,60 12,94 8,610 6,869 5,959 5,408 5,041 4,781 4,587 4,437 4,318 4,221 4,140 4,073 4,015 3,965 3,922 3,883 3,850

33



Slide 34 As can be seen in the formula of the previous slide the confidence limit depends very much on the number of measurements. This is demonstrated in this slide showing the confidence limits for a single measurement, for three and for ten measurements

Confidence Limits – Depending on n Confidence Limits are strongly dependent on the number of measurements CL (n=1) CL (n=1) CL (n=3) CL CL (n=1) (n=3) CL (n=10)

34


Slide 35 When talking about quality of chemical measurements trueness, precision, accuracy and error are some of the more important keywords. Therefore a clear definition is necessary (see also chapter 11, slides 36 and 44).



Trueness – Precision – Accuracy - Error Trueness The closeness of agreement between the true value and the sample mean

Precision The degree of agreement between the results of repeated measurements

Accuracy The sum of both, trueness and precision

Error The difference between one measurement and the true value 35



8

Basic Statistics

173

Slide 36

Linkage Improv ing trueness

The linkage between these keywords is shown in this figure with a target as example.

Improv ing accuracy

Error

Improv ing precision from: LGC, vamstat II 36



Slide 37 Significance testing is another topic of statistics. What does this mean? A typical situation for analytical chemists is where a reference material together with its certified value and uncertainty is given on the one hand and on the other hand there is the result of the analysis. The analyst wants to know whether the bias of his result is significant or just due to random errors.

Significance Testing - ? Typical Situation: We have analysed a reference material and we want to know, if the bias between the mean of measurements and the certified value of a reference material is „significant“ or just due to random errors.

This is a typical task for significance testing 37



Slide 38 The aim of significance testing is to make a decision about a population that is based on observations made from a sample from this population. This decision can only be made with a certain level of confidence. Therefore there can never be a guarantee of the correctness of the decision. If there is 95% confidence, there is 5% doubt.

Significance Testing A decision is made About a population Based on observations made from a sample of the population On a certain level of confidence

There can never be any guarantee that the decision is absolutely correct On a 95% confidence level there is a probability of 5% that the decision is wrong 38



174


Slide 39 Before we apply the machinery of Before Significance Testing statistics we always should inspect a Inspect a graphical display of the data before graphical display of the data. From using any statistics this we can see many details, which Are there any data that are not suitable? may not be revealed by the signific Is a significance test really necessary? Compare the statistical result with a ance test: commonsense visual appraisal We should look for “strange” data, A difference may be statistically significant, but not of any importance, because it is small which e.g. make no sense from a scientific point of view. Maybe we can see that there is no need at all for a significance test. We can crosscheck the statistical result with our common sense visual appraisal. And the most essential point: we possibly can see, that there is statistical significance but the difference is not important in magnitude compared with our quality needs. Koch, M.: Basi c Stati stics

39




Slide 40 The example in the last slide shows one of the fundamental points in the application of statistics to analytical results. Statistics are very useful tools to solve a lot of problems. But nevertheless they should always be applied with a critical view of the results, whether they make scientific sense.

The most important thing in statistics

No blind use 40


Slide 41 Significance testing can be divided into a small number of steps. It starts with the formulation of the Null hypothesis. This is the assumption, which is made about the properties of a population of data expressed mathematically, e.g. “there is no bias in our measurements”. The second step is the formulation of the alternative hypothesis, the opposite of the Null hypothesis, in the above example: “there is a bias”.



The Stages of Significance Testing - I Null hypothesis A statement about the population, e.g.: there is no bias (µ = xtrue)

Alternative hypothesis H1 The opposite of the null hypothesis, e.g.: there is a bias (µ ≠ xtrue) 41



8

Basic Statistics

175

Slide 42 In the next step a value for the test is calculated from the data and compared with the tabulated critical value. If the calculated value exceeds the critical value this indicates significance. To finalize the significance test the test statistics have to be evaluated with respect to the Null hypothesis. This enables us to make decisions and to draw conclusions.

The Stages of Significance Testing - II Critical value The tabulated value of the test statistics, generally at the 95% confidence level If the calculated value is greater than the tabulated value than the test result indicates a significant difference

Evaluation of the test statistics Decisions and conclusions 42





Slide 43 In the next few slides an example for significance testing in analytical chemistry is shown. The first point is the question that we want to ask. Is the result of our measurements (i.e. the mean) significantly different from the certified value of a reference material or is the difference just due to random variations?

Significance Test Example – the Question Is the bias between the mean of measurements and the certified value of a reference material significant or just due to random errors?

43





Slide 44 Before starting the calculations we can examine a graphical display of the results. The results of the measurements are shown as dots on the scale, the mean is marked as x . The vertical lines show the 95% confidence limits. In the upper case the certified value is outside these limits, therefore the bias is significant. In the lower case the certified value is inside the confidence interval, the bias is insignificant.

Significance Test example – Graphical Explanation 95% confidence interval for the population mean µ

significant

The reference v alue is outside the 95% confidence limits of the data set The bias is unlikely to result from random v ariations in the results The bias is significant

x true

not significant

x

95% confidence interval for the population mean µ

The reference v alue is inside the 95% confidence l imits of the data set The bias is likely to result from random v ariations in the results x true x

The bias is not significant

44



176


Slide 45 Let us translate this into mathematics. Significance Test Example The Null hypothesis (our assumption) Calculation says: There is no bias. The Null hypothesis: We assume there is no bias: x=x t⋅s t⋅s We calculate the confidence limits as Calculation of confidence limits x− < μ < x+ n n With the Null hypothesis shown above and translate our Null x−x t ⋅s t ⋅s >t = or t x− <x <x+ s hypothesis into a mathematical formula n n n If we use a CRM to estimate xtrue from x we have resulting in a formula for an observed to take into account also the uncertainty of the Student-t-factor tobserved. We can now reference value u and get x−x >t = t compare this observed value with the ⎛ s ⎞ ⎜ ⎟ +u ⎝ n⎠ critical value for 95% confidence and the degrees of freedom for our number of measurements. Since the reference values of a CRM only is a estimate of the true value, we have also have to consider the uncertainty of this value. This is done by extending the denominator in the last equation.

true

true

critical

true

observed

ref

ref

ref

critical

observed

2

2 ref


45




Slide 46 We get the critical value from the table of t-values. We have a two-tailed question, we want to have 95% confidence level, and with 10 measurements we have 9 degrees of freedom. Therefore we get from the table a critical value of 2.262.


60% 20% 0,3249 0,2887 0,2767 0,2707 0,2672 0,2648 0,2632 0,2619 0,2610 0,2602 0,2596 0,2590 0,2586 0,2582 0,2579 0,2576 0,2573 0,2571 0,2569 0,2567

75% 50% 1,000 0,8165 0,7649 0,7407 0,7267 0,7176 0,7111 0,7064 0,7027 0,6998 0,6974 0,6955 0,6938 0,6924 0,6912 0,6901 0,6892 0,6884 0,6876 0,6870

80% 60% 1,376 1,061 0,9785 0,9410 0,9195 0,9057 0,8960 0,8889 0,8834 0,8791 0,8755 0,8726 0,8702 0,8681 0,8662 0,8647 0,8633 0,8620 0,8610 0,8600

85% 70% 1,963 1,386 1,250 1,190 1,156 1,134 1,119 1,108 1,100 1,093 1,088 1,083 1,079 1,079 1,074 1,071 1,069 1,067 1,066 1,064

90% 80% 3,078 1,886 1,638 1,533 1,476 1,440 1,415 1,397 1,383 1,372 1,363 1,356 1,350 1,345 1,341 1,337 1,333 1,330 1,328 1,325

95% 90% 6,314 2,920 2,353 2,132 2,015 1,943 1,895 1,860 1,833 1,812 1,796 1,782 1,771 1,761 1,753 1,746 1,740 1,734 1,729 1,725

97,50% 95% 12,71 4,303 3,182 2,776 2,571 2,447 2,365 2,306 2,262 2,228 2,201 2,179 2,160 2,145 2,131 2,120 2,110 2,101 2,093 2,086

99% 98% 31,82 6,965 4,541 3,747 3,365 3,143 2,998 2,896 2,821 2,764 2,718 2,681 2,650 2,624 2,602 2,583 2,567 2,552 2,539 2,528

99,50% 99% 63,66 9,925 5,841 4,604 4,032 3,707 3,499 3,355 3,250 3,169 3,106 3,055 3,012 2,977 2,947 2,921 2,898 2,878 2,861 2,845

99,90% 99,80% 318,3 22,33 10,21 7,173 5,893 5,208 4,785 4,501 4,297 4,144 4,025 3,930 3,852 3,787 3,733 3,686 3,646 3,610 3,579 3,552

99,95% 99,90% 636,6 31,60 12,94 8,610 6,869 5,959 5,408 5,041 4,781 4,587 4,437 4,318 4,221 4,140 4,073 4,015 3,965 3,922 3,883 3,850

46



Slide 47 Now we can draw the conclusions: If the critical value tcritical exceeds the observed value tobserved we can say: there is no significant bias at the 95% level or one of the other formulations in the slide. But we cannot say: there is no bias.

Significance Test Example – Conclusions I If we find tcritical > tobserved Conforming to our Null hypothesis

We can say: We cannot reject the Null hypothesis We accept the Null hypothesis We find no significant bias at the 95% level We find no measurable bias (under the given experimental conditions) But not: there is no bias

47



8

Basic Statistics

177

Slide 48 On the other hand, if we find tcritical smaller than tobserved we can say: “we find significant bias at the 95% level” or “we reject the null hypothesis”. But we cannot say: there is bias. Since our calculations are based on a 95% confidence level, there is a chance of about 5% that we are wrong.

Significance Test Example – Conclusions II If we find tcritical < tobserved Not conforming to our Null hypothesis

We can say: We reject the null hypothesis We find significant bias at the 95% level But not: there is a bias, because there is roughly a 5% chance of rejecting the Null hypothesis when it is true. 48





Slide 49 The example we just looked at is called one-sample t-test. It compares the mean of analytical results with a stated value. This is a typical analytical question. The problem may be twotailed as in our example, where it doesn’t matter, if the analytical value is biased to the one or the other direction. Or the question could be one-tailed, e.g. if we want to know whether the copper content analysed in an alloy is below the specification.

One-sample t-test This test compares the mean of analytical results with a stated value The question may be two-tailed As in the previous example

Or one-tailed E.g.: is the copper content of an alloy below the specification? For one-tailed questions other t-values are used 49





Slide 50 If we have a one-tailed question we have to use other t-values. In the table shown in this slide we have to select the level of confidence from the first row for one-tailed and from the second row for two-tailed questions.


60% 20% 0,3249 0,2887 0,2767 0,2707 0,2672 0,2648 0,2632 0,2619 0,2610 0,2602 0,2596 0,2590 0,2586 0,2582 0,2579 0,2576 0,2573 0,2571 0,2569 0,2567

75% 50% 1,000 0,8165 0,7649 0,7407 0,7267 0,7176 0,7111 0,7064 0,7027 0,6998 0,6974 0,6955 0,6938 0,6924 0,6912 0,6901 0,6892 0,6884 0,6876 0,6870

80% 60% 1,376 1,061 0,9785 0,9410 0,9195 0,9057 0,8960 0,8889 0,8834 0,8791 0,8755 0,8726 0,8702 0,8681 0,8662 0,8647 0,8633 0,8620 0,8610 0,8600

85% 70% 1,963 1,386 1,250 1,190 1,156 1,134 1,119 1,108 1,100 1,093 1,088 1,083 1,079 1,079 1,074 1,071 1,069 1,067 1,066 1,064

90% 80% 3,078 1,886 1,638 1,533 1,476 1,440 1,415 1,397 1,383 1,372 1,363 1,356 1,350 1,345 1,341 1,337 1,333 1,330 1,328 1,325

95% 90% 6,314 2,920 2,353 2,132 2,015 1,943 1,895 1,860 1,833 1,812 1,796 1,782 1,771 1,761 1,753 1,746 1,740 1,734 1,729 1,725

97,50% 95% 12,71 4,303 3,182 2,776 2,571 2,447 2,365 2,306 2,262 2,228 2,201 2,179 2,160 2,145 2,131 2,120 2,110 2,101 2,093 2,086

99% 98% 31,82 6,965 4,541 3,747 3,365 3,143 2,998 2,896 2,821 2,764 2,718 2,681 2,650 2,624 2,602 2,583 2,567 2,552 2,539 2,528

99,50% 99% 63,66 9,925 5,841 4,604 4,032 3,707 3,499 3,355 3,250 3,169 3,106 3,055 3,012 2,977 2,947 2,921 2,898 2,878 2,861 2,845

99,90% 99,80% 318,3 22,33 10,21 7,173 5,893 5,208 4,785 4,501 4,297 4,144 4,025 3,930 3,852 3,787 3,733 3,686 3,646 3,610 3,579 3,552

99,95% 99,90% 636,6 31,60 12,94 8,610 6,869 5,959 5,408 5,041 4,781 4,587 4,437 4,318 4,221 4,140 4,073 4,015 3,965 3,922 3,883 3,850

50



178


Slide 51 If we don’t have one stated value, but two independent sets of data (e.g. two Two-sample t-test analytical results from different labo This test compares two independent ratories or methods) we have to use sets of data (analytical results) the two-sample t-test, because we have The question may be two-tailed or onetailed as well to consider the dispersion of both data Two-tailed: are the results of two methods sets. In the same way as above we significantly different One-tailed: are the results of method A have to look carefully, what our quessignificantly lower than the results of tion is: it may be two-tailed (are the method B results significantly different?) or onetailed (is the result from method A significantly lower than that from method B?) Koch, M.: Basi c Stati stics

51




Slide 52 The mathematics for the two-sample t-test looks somewhat more complex. Beneath the difference between the two means the standard deviations of both data sets and the number of data are involved in the formula. The degree of freedom is given by n1+n2-2.

Two-sample t-test – t-value The formula for the calculation of the tvalue is somewhat more complex: t observed =

( x1 − x 2 ) ⎛ 1 1 ⎞ ⎛ s12 (n1 − 1) + s22 (n2 − 1) ⎞ ⎟ ⎜⎜ n + n ⎟⎟ × ⎜⎜ (n1 + n2 − 2) ⎟⎠ 2 ⎠ ⎝ ⎝ 1

The degree of freedom for the tabulated value tcritical is d.o.f = n1+n2-2 52



Slide 53 But there is a prerequisite that has to be fulfilled, before we can apply the two-sample t-test. It is valid only, if the standard deviations of the data sets are not significantly different. This has to be tested using the F-test.

Two-sample t-test - Validity The two-sample t-test is valid only if there is no significant difference between the both standard deviations s1 and s2 This can (and should) be tested with the F-test

53



8

Basic Statistics

179

Slide 54 The F-value is calculated from the estimated variances s2 of the two data sets. The critical value Fcritical can also be found from a table. For that we need the degrees of freedom for both data sets.

F-test The F-test is a method of testing whether two independent estimates of variance are significantly different The F-value is calculated according to Fobserved=sA2/sB2, with sA2 > sB2 The critical value of F depends on the degrees of freedom dofA=nA-1 and dofB=nB-1 and can be taken from a table 54





Slide 55

F-values F statistics f or P=0.05

nB=10

degrees of freedom f or denumerator (B)

In the example shown in this slide we have an F-table for 95% confidence. We assume that there are 10 measurements for each data set. The degrees of freedom are 9 for both. Therefore we find the critical F-value to be 4.03.

1

2

degrees of freedom f or numerator (A) 3 4 5 6 7

8

9

10

1 647,79 799,50 864,16 899,58 921,85 937,11 948,22 956,66 963,29 968,63 2

38,51

39,00

39,17

39,25

39,30

39,33

39,36

39,37

39,39

39,40

3

17,44

16,04

15,44

15,10

14,89

14,74

14,62

14,54

14,47

14,42

4

12,22

10,65

9,98

9,61

9,36

9,20

9,07

8,98

8,91

8,84

5

10,01

8,43

7,76

7,39

7,15

6,98

6,85

6,76

6,68

6,62

6

8,81

7,26

6,60

6,23

5,99

5,82

5,70

5,60

5,52

5,46

7

8,07

6,54

5,89

5,52

5,29

5,12

5,00

4,90

4,82

4,76

8

7,57

6,06

5,42

5,05

4,82

4,65

4,53

4,43

4,36

9

7,21

5,72

5,08

4,72

4,48

4,32

4,20

4,10

4,03

3,96

10

6,94

5,46

4,83

4,47

4,24

4,07

3,95

3,86

3,78

3,72

4,30

nA=10 55



Slide 56 From the comparison of our observed F-value and the critical F-value we can make our decision. If the observed value is smaller than the critical value we can say: The estimated variances are not significantly different at the chosen confidence level.

F-test - Decision If Fobserved < Fcritical than the variances sA2 and sB2 are not significantly different On the chosen confidence level

56



180


Slide 57 The two-sample t-test is only applicable, if the data are collected from analysing the same sample several times. If the data come from the analysis of different samples where the differences between the samples are much greater than the differences between the two methods or the two laboratories, it is necessary to apply the paired t-test.

Paired t-test Two different methods are applied for measuring different samples 3

Two-sample t-test is inappropriate, because differences between samples ar much greater than a bias between the two methods

Method A Method B

2,5 2 1,5

Î paired t-test 1 0,5 0 sample 1

sample 3 sample 2

sample 5 sample 4

sample 6 57





Slide 58 In this test the calculations are not done with the data itself, but with the differences between the two methods/ laboratories. These differences are tested for a significant difference from zero with a one-sample t-test.

Paired t-test - Principle The differences between both methods are calculated A one-sample t-test is applied on the differences to decide whether the mean difference is significantly different from zero

58





Slide 59 As described in slide 45 the value tobis calculated with xref = 0 and the critical value tcritical is taken from a table as shown above.

served

Paired t-test – Test Statistics The t-value is calculated according to:

tobserved =

x diff s diff n

The critical t-value is taken from the ttable for the desired confidence level 59



8

Basic Statistics

181

Slide 60 In summary it can be stated, that there are many helpful statistical tools for the analytical chemist. Although these tools cannot be a “cure-all”, every analyst should know how to handle these tools in order to answer his and his customers’ questions.

Statistics There are many statistical tools for the analyst to interpret analytical data Statistics are not a “cure-all” that can answer all questions If the analyst uses statistics with a commonsense, this is a powerful tool to help him to answer his customers or his own questions 60



Slide 61 There is a lot of literature about statistics and especially for analytical chemists. As an example two useful books and training software are recommended here for further details about statistical tools for analytical chemists.

Recommended literature and training software LGC, VAMSTAT II, Statistics Training for Valid Analytical Measurements. CD-ROM, Laboratory of the Government Chemist, Teddington 2000 H. Lohninger: Teach/Me - Data Analysis. Multimedia teachware. Springer-Verlag 1999 J.N. Miller and J.C. Miller: Statistics and Chemometrics for Analytical Chemistry. Prentice Hall Publisher 2005 T.J. Farrant: Practical Statistics for the Analytical Scientist – a Bench Guide. Royal Society of Chemistry for the Laboratory of the Government Chemist (LGC), Teddington 1997 Koch, M.: Basi c Stati stics In: W enclawiak, Koch, Hadj icostas (eds.)

61


Bibliography Farrant TJ (1997) Practical Statistics for the Analytical Scientist – a Bench Guide. Royal Society of Chemistry for the Laboratory of the Government Chemist (LGC), Teddington LGC (2000) VAMSTAT II – Statistics Training for Valid Analytical Measurements. CD-ROM, Laboratory of the Government Chemist, Teddington 2000 Lohninger H (1999) Teach/Me - Data Analysis. Multimedia teachware. SpringerVerlag Miller JN, Miller JC (2005) Statistics and Chemometrics for Analytical Chemistry. Prentice Hall Publisher

9

Calibration

Michael Koch

Slide 1 Most chemical analytical methods need a calibration to convert the Contents meaurement signal into an analytical Introduction result. This chapter describes the Basics of Calibration basics of calibration, different Limits of detection, quantification possibilities, how to perform it and the Standard Addition Method information derived from it. The detection and quantification capabilities of analytical methods often are important if they are used at trace levels of analytes. The description of the standard addition method, a special calibration in the sample finalises the chapter. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


1

© Springer-Verlag, Berlin Heidelberg 2010 2008


Slide 2 Calibration is the link between the signal of a measurement (e.g. extinction Introduction in photometry or peak area from a Calibration is an important process in detector in chromatography) and the Establishing the link between a signal of quantity we intend to measure. the measuring instrument and the associated quantity (e.g. concentration) of If we use a standard solution traceable the measurand to a stated reference, we ensure the Establishing traceability traceability of our measurement by Method validation to get the performance characteristics extending the traceability chain (for more details on traceability see chapter 10). From the basic calibration of our method we can derive some performance characteristics of the method. This is important for method validation (see chapter 11)

2

Koch, M.: M., Glu Calibration sch ke, M.: Control Charts





183

184


Slide 3 Analytical measurements are based on the fact that the response actually being measured varies with what we want to determine. Measurement generally means comparison of the unknown with the known. So, in calibration we compare the signal from the unknown amount of analyte in our sample with the signal of the known amount in our calibration sample.

Introduction

What is Calibration? Calibration is the process of establishing how the response of a measurement process varies with respect to the parameter being measured The usual way to perform calibration is to subject known amounts of the parameter (e.g. using a measurement standard or reference material) to the measurement process and monitor the measurement response 3

Koch, M.: M., Glu Calibration sch ke, M.: Control Charts In: W enclawiak, Koch, Hadj icostas (eds.)

© Springer-Verlag, Berlin Heidelberg 2010 2008 Quality Assurance in Analytical Chemistry – Training and Teaching (2nd ed.)

Slide 4 Of course we want to cover a certain range of the quantity we want to measure (e.g. concentration) with our measurement (the working range). So we need a mathematical function between the signal and the concentration range valid over the whole working range. But we also get statistical information and other characteristics from the calibration data.

Introduction

Two Major Aims Establishing a mathematical function which describes the dependency of the system’s parameter (e.g. concentration) on the measured value Gaining statistical information and characteristics of the analytical system, e.g. sensitivity, precision 4



Slide 5 There are different concepts for the calibration. External calibration uses the measurement of separate samples containing known amounts of analyte and we compare the signal from both, the calibration sample and our unknown sample. This method requires that the differences in the matrix of sample and calibration sample does not significantly influence the response. The use of an internal

Introduction

Calibration Concepts External standard Internal standard Standard addition

5



9

Calibration

185

standards includes addition of a known amount of a substance, which has properties similar to the analyte. Quite often internal standards are used to correct for insufficient recovery rates. The standard addition procedure is a calibration in the sample. Known amounts of analyte are added to the sample and from the increase in signal the original content is extrapolated (see slide 47) Slide 6 With calibration we define the working range, where we are sure that we can analyse the sought component in a way which is fit for the intended purpose.

Introduction

Goals of Calibration “Ability to calculate a (measurement) result in a secure (safe) working range” (Funk, W., Dammann, V., and Donnevert, G.: “Quality Assurance in Analytical Chemistry”)

Slide 7

6


This slide describes the steps we have to follow. We start with choosing the range we want to cover with our analysis. Than we measure some calibration standards in this range. We try to apply a linear regression, but we also check for the validity of this choice. If we succeed, we calculate the performance characteristics of our method and finally fix the working range.


Introduction

First Steps to the Goal Establishing the calibration function

Choosing the preliminary working range Measuring several calibration standards Linear regression Test of non linear regression Test of variance homogeneity Calculate performance characteristics Fix the working range 7



Introduction

Slide 8 In the routine use of the method we calculate the measurement results from the signal using the analytical function derived from the calibration function. And finally of course we report our result.

In Routine Calculating the (measurement) results Conversion of the calibration function into an analytical function Reporting the measurement results

8



186


Slide 9 The mathematical description of the link between signal and the quantity Basics of Calibration intended to be measured should be as Mathematical Functions simple as possible. If we have a linear simple linear function without intercept relationship and no blank response, i.e. y=mx linear function no signal, if the analyte is absent, we (intercept b, slope a) could use a simple linear function y = a + bx quadratic function without intercept. If we cannot exclude (intercept b, slope 2cx+b) that we have a blank signal we add an y = a + bx + cx2 intercept. The calibration function is then described by slope and intercept. In cases where we don’t have a strict linear relationship we could use a quadratic function. These are the functions commonly used in analytical chemistry. Of course, in special cases more sophisticated functions might also be used. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


9



Slide 10 Linear regression, or more exact, linear least-squares regression, is based on minimizing the sum of the squared vertical deviations (residuals) from the regression line.

Basics of Calibration

Principle of Linear Regression

Minimizing the sum of the squares of the residuals Koch, M.: M., Glu Calibration sch ke, M.: Control Charts

Slide 11


ISO 8466 describes how to perform calibration. Part 1 is covering the linear regression and part 2 the second order calibration strategy.


10


International Standards ISO 8466 Water quality– Calibration and evaluation of analytical methods and estimation of performance characteristics Part 1: Statistical evaluation of the linear calibration function Part 2: Calibration strategy for non-linear second order calibration functions 11



9

Calibration

187

Slide 12 The calibration function which‘ever chosen is describing how the signal depends on the analyte content x. The inverted function, the analytical function is used in the routine application of the method to calculate a content from the signal of an unknown sample.


Analytical Function / Calibration Function With calibration standards we get a measurement result y for each content x of the analyte in the standard With that we get (by regression analysis) the calibration function

y = f (x ) If we invert the function we can calculate the content of analyte in the unknown sample from the result of the measurement. This function is the analytical function

xˆ = f ( yˆ ) 12


Slide 13


The basic calibration of a method only covers the final measurement step without any preceding sample preparation. Pure analytical standard solutions are used here. Of course this does not cover the whole analytical process. So method characteristics for the basic calibration are not transferable to the whole analytical process. During validation the influence of other matrix constituents has to be investigated.



Basic Calibration With the Basic Calibration only the measurement step itself is calibrated I.e. no sample preparation like extraction, digestion etc. is done We simply analyse standards in pure solvent

13



Slide 14 Basics of Calibration Before we start we have to decide Choosing the Preliminary Working Range about a preliminary working range. The most important point is the purpose Take into consideration The practical application of the analysis (the of the future analyses. In which range purpose) do we expect the quantities to be The possibilities that are technically feasible Measurement results at the lower application limit must measured? Of course there are technical be significantly different from blanks The requested analytical precision (or measurement limitations. For very low concentrations uncertainty) has to be achieved over the whole working range we have to ensure that the signal If a linear regression procedure has to be applied the variances have to be homogeneous over the whole triggered by this content is significantly range and linearity has to be assured different from the signal of the blank. There also might be requirements on the uncertainty of the measurement, which might not be fulfilled at the lower end of the preliminary working range. If we want to use a linear calibration strategy we have to ensure that the variances are sufficiently homogeneous and that there is no significant deviation from linearity. 14





188


Slide 15 Basics of Calibration The first step in the laboratory is the Preparation of the Standard Samples preparation of the standard solutions. For the basic calibration we will use Requirements: Purity, matrix free or defined matrix sufficiently pure material which is free Homogeneity from interfering compounds. We have Representative for real samples Species similar in chemistry to ensure the homogeneity of the Same oxidation state etc. samples and the representativeness Stability, preserveability No influence on the sample from the container and regarding the characteristics described external conditions in the slide. Of course the samples have to be sufficiently stable for the time period within which they are intended to be used. If necessary, we have to preserve the samples. Storage of the samples has to be organised in such a way that the integrity of the sample is not influenced. 15





Slide 16 Basics of Calibration Preparation of standard samples Preparation of the Standard Samples always should be as accurate as possible. Therefore gravimetric procedures Production of standard samples Consider precision of balance and volumetric should be preferred compared to equipment volumetric ones and several dilutions Weighings are always more precise and therefore to be preferred should be avoided since each dilution Avoid successive dilutions step adds to the uncertainty. For a Prepare 6...10 standard samples, equidistant over the whole working range basic calibration we need 6 to 10 standard samples. They should be distributed equidistant over the whole working range. Linear regression requires equidistant distribution. Otherwise a weighted regression would be needed. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts

Now we apply the usual linear regression procedure, which delivers slope and intercept of the calibration function. From the residuals, i.e. the vertical distances of the calibration points from the regression line, the residual standard deviation can be calculated. This standard deviation is a quality indicator for the calibration function.



Linear Calibration

Y

Slide 17

16



Regression analysis delivers the calibration function y = a + bx slope (sensitivity) b=

∑ [(x − x ) ⋅ (y − y )] ∑ (x − x ) i

i

2

i

Intercept X

a = y − bx

Residual standard deviation (vertical scattering of the results around the regression line) sy =

∑ (y

− yˆ i )

2

i

N −2

w ith yˆ i = a + bxi

Process standard deviation

sx 0 =

Process variation coefficient

Vx 0 =

sy b sx0 ⋅100% x 17



9

Calibration

189

The correlation coefficient r² does not indicate the quality. If we divide the residual standard deviation by the sensitivity (the slope of the function) we get the process standard deviation and the process variation coefficient respectively. Slide 18 Basics of Calibration

Second Order Calibration Function y = a + bx + cx2 Calculations are somewhat more difficult here For details see ISO 8466-2

Y

If the relationship between the signal and the concentration is not linear, we may apply a second order calibration function. For details about this slightly more difficult calculation see ISO 8466-2.

X

18


Slide 19


The formula for the residual standard deviation is a bit different. This reflects that the degrees of freedom are one less. The slope of the function and therefore also the sensitivity is concentration dependent. So usually the sensitivity in the middle of the working range is reported. We may also calculate the process standard deviation and process variation coefficient in the middle of the working range.



Second Order Calibration Function Residual standard deviation sy =

∑ (y

− yˆ i )

2

i

N −3

w ith yˆ i = a + bxi + cxi2

Sensitivity First order derivation of the calibration function

S ( x) = b + 2c ⋅ x

E ( x ) = b + 2c ⋅ x

In the middle of the working range

Process standard deviation sx0 =

sy

E(x )

Process variation coefficient Vx 0 =

sx0 ⋅ 100 % x 19



Slide 20 Basics of Calibration

Linearity Check If possible, the linear calibration function should be used, only in special circumstances second order calibration should be used Visual linearity check 0,6

Graphical display incl. calibration line If non-linearity is obvious you may abstain from a statistical linearity check

0,5

measurement result

Usually linear calibration functions are preferred. To check for linearity the easiest thing is a visual check by inspection of the calibration data together with the regression line. Sometimes non-linearity is so obvious, that no statistical test is required.

0,4 0,3 0,2 0,1 0 0

2

4

6

8

10

concentration

20



190


Slide 21 Basics of Calibration If it is not clear, the Mandel-test may Linearity Check be applied for linearity check. We Mandel test Calculation of linear calibration function y=a+bx and the 2 calculate the linear and the 2nd order order calibration function y=a+bx+cx including the respective residual standard deviations s (linear) and s calibration function and the respective (quadratic) Calculation of the differences of variances DS : residual standard deviations. If the DS = ( N − 2) s − ( N − 3) s with degreeof freedomf = 1 F-test (as described in the slide) delivers DS Check with F-test F = s a significant difference between the Comparis on with the critical value from the table for f =1, f = N-3, P=99% F residual standard deviations, this F , varianc es are not homogeneous answer on the question, whether they Possible consequenc es: Reduced working range are significantly different or not. Weighted regression In cases where we have inhomogeneous variances we may reduce the working range or use a regression procedure weighted with variances at different concentrations. si2 =

observed

observ ed

y ij − y i

2

ni − 1

2 N 2 1

critical


24




Slide 25 Basics of Calibration We must not accept outliers in a Outlier Test calibration data set. We also can test Calibration data always have to be free from this with an statistical outlier test. outliers Thereby we have to consider that the The outlier test assumes that the chosen regression approach is correct outlier test assumes the chosen Potential outliers can be identified from the approach for the regression function to residual analysis First calculate the residual standard deviation be correct. First we should have a look sy,A1 using all results; than eliminate the on the plot of the residual analysis, potential outlier and calculate again sy,A2 Check with F-test or t-test because from there we can recognise potential outliers. We calculate the regression both with and without the potential outlier. Then we can apply either the F-test or the t-test. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts

25




Slide 26 Basics of Calibration

With the F-test we can look for significant differences in the residual standard deviations, as shown in the slide

Outlier Test using the F-Test The residual standard deviations are checked for significant differences Calculate Fobserved =

( N A1 − 2) s y2A1 − ( N A 2 − 2) s y2A 2 s y2A 2

And compare with the critical value from a statistical table for f1=1, f2=NA2-2, P=95% If Fobserved < Fcritical, no outlier is identified

26



192


Slide 27 Or we may calculate the prognostic interval of the regression function without the potential outlier, i.e. the interval within which we would expect an additional value to lie with a certain confidence. If our suspect value lies within this interval, we cannot reject it as an statistical outlier.


Outlier Test using the t-Test Calculate the prognostic interval of the regression line without the potential outlier PI ( yˆ A ) = yˆ A ± t ⋅ s y A 2 ⋅ 1 +

1 + NA

(x A − x )2

∑x

2 i

−

1 = a2 + b2 ⋅ x A ± t ⋅ s y A 2 ⋅ 1 + + NA

t = tabulated value from the t distributi on ( P = 95%, f = N A-2)

1 (∑ xi )2 NA

(x A − x )2

N A = N-1 x A = concentrat ion of the potential outlier x = mean of all x i ( without x A )

2 1 ∑ xi2 − N (∑ xi ) A

If the potential outlier is located within the prognostic interval, it‘s no outlier If an outlier is identified statistically, the error source has to be found and eliminated. Than the complete calibration has to be repeated. 27



Slide 28 What we have seen up to here is the Calibration Strategies in Routine basic calibration that delivers method Analysis characteristics for the pure physical The basic calibration as described up to measurement in the validation and here is part of the (re-)validation of an re-validation procedure. Many analytical analytical method For routine use calibration strategies methods however require a frequent, with less effort are used sometimes daily calibration. Of course The effort made depends on the there is no need to have a 10 point demands of the customer and the stability of the method calibration for everyday calibration. The choice of the strategy used is the responsibility of the laboratory. It depends on the customer’s requirement on accuracy and the stability of the method. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


28



Slide 29 We can choose both on the number of calibration standards and on the frequency of calibration. The one extreme for very stable methods is to use one calibration over several months. If we want we can check of course the validity of this calibration with one calibration standard. If the method and the instrument are less stable, there might be a need for more frequent full calibrations with several calibration standards.

Calibration Strategies in Routine Analysis Number of calibration points in routine Where the calibration of the method is very stable a one-point calibration to verify a previous multipoint calibration may be sufficient In other, less stable circumstances a 3- or 5-point calibration may be needed

Frequency of calibration Also depends on the stability of calibration Some analytical methods need a daily calibration whereas other calibrations may last for months. At least check of the calibration is adviceable in any case Koch, M.: M., Glu Calibration sch ke, M.: Control Charts In: W enclawiak, Koch, Hadj icostas (eds.)

29


9

Calibration

193

Slide 30 In case where we have sample prepaInternal Standard ration steps with incomplete recovery Advisable for methods including a complex the use of an internal standard is sample preparation procedure like extraction and clean-up advisable. We have to look for a sub Addition of a known amount of a substance stance which is so similar to the different from the analyte and not present in the sample, but chemically behaving in the analyte that the chemical behaviour is same way as the analyte close to that of the analyte. We add a Correction of the measurement result for the analyte with the recovery rate of the internal known amount of this internal standard standard to our original sample and In mass spectrometry isotope marked analytes are often used for this purpose determine the recovery. Assuming that we have the same recovery for our analyte we correct our result with this recovery. In mass spectrometry isotope marked analytes are ideal internal standards and therefore quite often used. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


30



Slide 31 The lower end of the working range is limited by the detection capabilities of the analytical method. Limit of detection and limit of quantification (sometimes also called limit of quantitation or limit of determination) describe these capabilities of the method.

Limits of Detection, Quantification Limit of Detection Limit of Quantification (Quantitation, Determination)

31



Slide 32


As the name implies the LoD describes the lowest concentration that can be detected with a certain level of confidence. From here we can state that the analyte is really present. This does not mean that we can quantify the content of the analyte with a certain confidence. This is only possible at concentrations above the LoQ.

Limits of detection, quantification


Limit of Detection (LoD) Limit of Quantification (LoQ) Are used to quantify detection and quantification capabilities (the lower end of the working range) Limit of detection (LoD) The lowest concentration that can be detected with a certain level of confidence

Limit of quantification (LoQ) the minimum content that can be quantified with a certain confidence 32



194


Slide 33 Limits of detection, quantification Most analytical procedures do not Specification of Measurement consist of a physical measurement step Process only, but may include chemical sample LoD and LoQ cannot be specified in the preparation steps. In addition there absence of a fully defined measurement process including interferences and type of might be some substances present that sample matrix interfere with our measurements and "Interference free detection limits" and "Instrument detection limits", for example, do other constituents (the matrix) may not specify the measurement capabilities of a complex measurement process including influence the sensitivity of the method. sample preparation If we simply determine the interference free or instrument detection limits, this does not describe the detection and quantification capabilities of our complete analytical method. (IUPAC Orange Book)



33



Slide 34 There are many ways to calculate LoD values. Unfortunately there is no standardised way accepted by the scientific community in all fields of analytical chemistry. We want to have a closer look on two methods, both described in the IUPAC “Orange Book”.


Calculation of LoD There is no uniform way to calculate LoD values in the scientific community Two possibilities are described in the following slides (both taken from IUPAC Orange Book)

34



Slide 35


The simple approach is just using the mean value of several determinations of blank samples plus a multiple (factor k) of the standard deviation of these measurements. With the choice of k we define the level of confidence.



LoD – Simple Approach The value of the LOD is given by LoD = x b l + k ⋅ sb l with x bl = mean of blanks sbl = standard deviation of blanks k = numerical factor defining the confidence level

35



9

Calibration

195

Slide 36 We have to make a sufficiently high number of blank measurements. If the measurement of blanks does not deliver a signal we set x bl = 0 and use


LoD – Simple Approach The mean of measurements of blanks and their standard deviation must be found experimentally by making a sufficiently large number of measurements A value of 3 for k is strongly recommended

the standard deviation of measurements with a very low content. At low concentrations non-Gaussian distributions IUPAC recommends the use of k=3. are more likely The mean and standard deviations are only Since we cannot expect that the signals estimates of the population characteristics So the 3 s value usually corresponds to a of very low concentrations are confidence level of about 90% normally distributed and since we only can estimate the mean and the standard deviation from a few measurements the confidence level for k=3 is expected to be around 90%. bl

36





Slide 37 Now we want to have a closer look on the situation. We have to consider and avoid two different error possibilities. We want to exclude to think that the analyte is present where it is indeed not. This would be a false positive answer, a type I error. But on the other side we also want to avoid errors, where we say the analyte is absent and it is indeed present, a false negative or type II error.


LoD – More Sophisticated Approach Fundamentals Two kind of errors have to be considered Type I – false positive Probability of a type I error is called α

Type II – false negative Probability of a type II error is called β

37



Slide 38 Limits of detection, quantification

From the distribution of signals of blank measurements we can derive the critical value. This value is defined by the one-tailed error probability α of the statistical distribution. If the signal is above this critical value we have a low probability (α) for a false positive error.

LoD – More Sophisticated Approach Critical Value The critical value is derived from the statistical distribution of the signal of measurements of blanks If the corresponding signal is exceeded we recognize with an error probability (onetailed) of α that the analyte content in the sample is higher than in a blank We have a low probability for a false positive error 38



196


Slide 39 Limits of detection, quantification This low probability is shown in the LoD – More Sophisticated Approach left of the two distributions in this Critical Value graph, the statistical distribution of blank measurements. At a signal corresponding to the critical value we have the low probability for a false positive error, described by the black part of the distribution. If the analyte is really present at a But the probability for a false negative error at the critical value is high (50%) concentration of the critical value this means, that in 50% of the measurements we would find a signal above the critical value and in 50% a signal below the critical value. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


39



Slide 40 But since we want to define the LoD in such a way that the probabilities both for a false positive and a false negative error are low, we have to find a value where also the probability for a false negative error β is low. IUPAC recommends to choose α=β=0.05.


LoD – More Sophisticated Approach The LoD Value The LoD value is characterised by a low probability for a false positive error (α) and for a false negative error (β) α=β=0.05 is recommended

40



Slide 41


In the graph now an additional distribution of values is shown where we have only a low probability (black end of the distribution) to get a signal below the critical value. Now the probabilities for both error types are low and we can accept the mean of this population as LoD.



LoD – More Sophisticated Approach The LoD Value

41



9

Calibration

197

Slide 42 Let us compare the different meanings Limits of detection, quantification Critical Value ↔ LoD of the critical value and the LoD. If we measure a signal above the critical The critical value is the decision limit for value we know (with a high probabilthe presence of the analyte ity) that the analyte really is present. The LoD describes the minimum content which can be detected with So we can use this value as a decision stated high probability limit for the presence of the analyte. Only the LoD, not the critical value may The LoD gives us the minimum be used as maximum guaranteed content of the analyte content where we can be sure that we really detect the analyte with a high probability. If we want to state a maximum guaranteed content (“< X”) we can only use the LoD for that purpose. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


42



Slide 43 Limits of detection, quantification Now we want to calculate both values from the statistical distribution of Calculation of Lc and LoD blank values or very low contents. We If we assume a Gaussian distribution of assume normal distribution and homothe results and homogeneity of geneity of variances in the range variances over the concentration range between the blank and the LoD. the limit for an one-tailed error probability α of 0.05 is at µ + 1.64 σ. The one-tailed 95% limit for a normal If we decide for α=β=0.05 we get distribution is at μ + 1.64 σ (see also Lc = xb l + 1.64 ⋅ sb l the chapter 8).We estimate μ from the LoD = x b l + 3.28 ⋅ sb l mean of several blank measurements and σ from the standard sbl of these measurements. If we decide to use α=β=0.05, we get the formula for LC and LoD shown in the slide. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


Slide 44 There is another simple approach to define the detection limit, mainly used for chromatographical methods. The noise of the signal without a peak is quantified and a signal-to-noise ratio of 3 (sometimes 2) is used as detection limit.

43




Signal-to-Noise Ratio In many analytical applications a signalto-noise ratio of 3 (sometimes 2) is used as definition of detection limit

44



198


Slide 45 Now we turn from detection to quantification of the analyte. The slide shows the definition of the LoQ from the IUPAC “Orange Book”. Note the word “adequately” in the sentence. That means that we have to define what is adequate, what is fit for the purpose.


Limit of Quantification (LoQ) Quantification limits are performance characteristics that mark the ability of a analytical method to adequately “quantify” an analyte (IUPAC Orange book)

45



Slide 46 Generally a relative standard deviation of 10% is regarded as being adequate. Therefore the LoQ can be calculated as the k-fold multiple of the standard deviation at the LoQ. IUPAC recommends to use k=10 (corresponding to a relative standard deviation of 10%). If we assume homogeneity of variances in this very low concentration range the LoQ is 10·sbl.


LoQ The ability to quantify is generally expressed in terms of the signal or analyte (true) value that will produce estimates having a specified relative standard deviation (RSD), commonly 10 %

LoQ = k ⋅ sLoQ

with sLoQ = standard deviation at the LoQ concentrat ion k = multiplier (reciproca l = selected quantifyin g RSD)

The IUPAC default value for k is 10 If the variances are homogeneous sLoQ = sbl Koch, M.: M., Glu Calibration sch ke, M.: Control Charts In: W enclawiak, Koch, Hadj icostas (eds.)

46


Slide 47 The standard addition method is a calibration in the sample. Known amounts of analyte are added to the samples and the signal-concentration regression line is extrapolated to a signal of zero.

Standard Addition Method

Standard addition is calibration in the real sample by stepwise addition of known amounts of the analyte

47



9

Calibration

199

Slide 48 Standard addition method The standard addition methods is a When should the Standard very good tool for samples where the Addition Method be Used? sensitivity of the method is strongly If the composition of the sample matrix influenced by other sample constituents. has high influence on the accuracy of Especially where no matrix adjusted analysis external calibration is available the If no matrix-adjusted calibration standards are available benefits of the standard addition If only few samples have to be analysed method are obvious. If we have to analyse only a few samples the effort for the standard addition method is nearly the same as for an external calibration, but it gives us more confidence. Koch, M.: M., Glu Calibration sch ke, M.: Control Charts


Slide 49

48



Standard addition method

Requirements

There are a few requirements for the Analytical results that are corrected for blank application of the standard addition and background Linear relation between concentration x method. The analytical results have to signal y be corrected for blank. Otherwise we Homogeneity of variances would add the blank value to our Possibility to homogeneously divide samples into sub-samples sample content. Since we are using Analyte can precisely be added to the sample linear regression we need a linear relationship between signal and concentration. As stated above the homogeneity of variances is also a prerequisite for linear regression. We want to divide our sample into several sub-samples and spike them with known amounts of analyte. This means that we need to divide the sample homogeneously and to precisely add the analyte.

49






Slide 50

Procedure Take n sample aliquots

Add linear increasing amounts of the analyte The procedure starts with dividing the to (n-1) sample aliquots in equidistant steps sample into n sub-samples. We spike Apply linear least square regression to the n-1 sub-samples with the analyte in pairs of values → y = a +b⋅x equidistant steps and measure all n Extrapolite to the intersection with the x-axis sub-samples. We use least-square This value delivers the sought content → x = − x = −a / b regression to calculate the regression line and extrapolate to the intersection with the x-axis, i.e. we assume that our regression line is shifted to the left by the signal of our sample content. The x-axis intercept therefore delivers our sought content. A

( y =0 )

50





200


Slide 51 Here we see an example. The original sample and four spiked sub-samples were analysed. The regression line intersects the x-axis at –xA. So xA is our sample content. The advantage of the standard addition method is, that it delivers accurate results even if the recovery is not complete, provided it is constant for all sub-sample determinations. In the graph also the confidence interval of the regression line is shown.


Graphical Presentation

regression line confidence interval xA

51





Slide 52 This confidence interval can be used to quantify the uncertainty of the result as far as it is resulting from the calibration procedure. The formula given in the slide shows the calculation of that confidence interval.


Uncertainty The uncertainty of the calcualted value xA may be quantified from the half-width of the confidence interval Δx A =

t f ,α ⋅ s y ,x b

[x − (− x A )] 1 + z n ⋅ n A ∑ x zi − x z 2 2

⋅

(

)

x A = half - width of the conf idenceinterv alof x A t f,α = two - tailed quantile of the t - distribution (probabili ty α ) x z = arithmetic mean of all x zi

∑ (x

zi

− xz

)

2

= sum od squares of dev iations of all x zi

52



Bibliography Funk W, Dammann V, Donnevert, G (2006) Quality Assurance in Analytical Chemistry. 2nd edition, Verlag Wiley VCH Weinheim ISO 8466-1:1990 – Calibration and evaluation of analytical methods and estimation of performance characteristics – Part 1: Statistical evaluation of the linear calibration function ISO 8466-2:2001 – Calibration and evaluation of analytical methods and estimation of performance characteristics – Part 2: Calibration strategy for non-linear secondorder calibration functions IUPAC (1997) Orange book – “Compendium on Analytical Nomenclature”, 3rd edition, available from www.iupac.org

10 Metrology in Chemistry and Traceability of Analytical Measurement Results

Ioannis Papadakis and Bertil Magnusson This gives an overview of metrology in analytical chemistry as well as describing the role of measurement traceability. The traceability part of the presentation is based on the CITAC position paper on measurement traceability (Traceability in Chemical Measurement, Accred. Qual. Assur. (2000) 5:388-389) Slide 1 First we will discuss today's needs for metrology, then the fundamentals of metrology will be presented followed by some information about the international measurement system and the presentation will end with discussion about traceability of analytical measurement results.

Index Metrology - need for measurement quality International Measurement System Traceability of measurement results

1

Papadakis, I ., Magnusson, B.: Metrolog y in Chemi str y and Traceabi lit y In: W enclawiak, Koch, Hadj icostas (eds.)



Slide 2 Starting with the ISO definition of metrology: metrology is the science of measurement. It is important to note that there is no distinction between theoretical or practical aspects or level of uncertainty or in whatever field of science or technology the measurements occur.

Metrology – Science of Measurement Metrology includes all theoretical and practical aspects of measurement, whatever the measurement uncertainty and field of application. (VIM, 3rd edition)

2





201

202


Slide 3 But what is a measurement? Measurement is obtaining a measurement result - a quantity value and an uncertainty.

What is a Measurement ? Process of experimentally obtaining one or more quantity values Quantity is a property which has a magnitude that can be expressed as a number and a unit e.g. Quantity: Cadmium (mass)concentration Quantity value: 12 mg/l Cd Measurement result: 12 ± 2 mg/l Cd (VIM, 3rd edition)

3




Slide 4 And what is measurement quality? Main focus is that measurement need to be comparable over space and time and here we need metrology.

What is Measurement Quality ? Results should be fit for purpose – regarding several parameters e.g uncertainty, price and comparability Comparability - measurements need to be comparable over: Time 1900 2000 2100 year Between different laborat ories Between different countries

measured once – accepted everywhere 4




Slide 5 It should also be clear that unreliable measurements lead to duplication of work, use of extra resources, lack of trust between trading partners, create negative economic impact and often lead to accidents or disasters.

Lack of Measurement Quality can Lead to:

Duplication of measurements Use of extra resources Lack of trust Negative economic impact Disasters/accidents 5




10

Metrology in Chemistry and Traceability of Analytical Measurement Results

203

Slide 6 Let’s see now some examples, which show the importance of measurements for today’s society. The first example (picture) is relevant to physical metrology.

Examples of lack of measurement quality

6




Slide 7 The picture in the previous slide is a scientific space ship. Another scientific spaceship, the Mars Climate Orbiter, was completely destroyed on September 1999. The reason for this disaster was that two different NASA teams were using different systems of units. Somewhere in the conversion a mistake was made that caused the loss of the spacecraft. This probably would have been avoided if the same system of units had been used.

Mars Climate Orbiter ...confusion about units leads to crash... On 23 September 1999 the Mars Climate Orbiter,one of the missions in a long-term program of Mars exploration, burned out completely. The accident was not due to a technical problem, but the result of the different measurement units used by the NASA teams. One team used the metric system for spacecraft operation, while the other used the English units. This information was critical to the maneuvers required to position the spacecraft in the proper Mars orbit and led to the loss of the orbiter. The fate of the Mars Climate Orbiter clearly shows the need for standardization of units 7




Slide 8 In order to make it more explicit for chemical measurement, three examples are chosen from different chemical measurement fields, which show the importance of chemical measurement. The first originates from petroleum industry. A single measurement mistake cost 10 million US dollars to the company.

Difference $ 10 Million A subsidiary of an oil company in the Far East analysed a batch of petrol. Their local lab established that the gum content (components in the gasoline that polymerize during combustion) was much too high. On the basis of this analysis the company sold the batch to a trader for a much lower price. The trader asked a second lab to perform an analysis in order to find out what he could do with the off-spec petrol. He was very pleasantly surprised to find that the gasoline was actually on-spec and he was able to make a healthy profit selling the batch for the normal price. The oil company only found out much later that the problem was not the petrol, but an error at their own lab. By then this error had already cost them $ 10 million. (Buskes and van Gerven) 8




204


Slide 9 The second example originates from the construction business. Because of inadequate quality control measurements on the construction materials the whole project was considerably delayed and the total cost, which was originally estimated as 900 million US dollars, exceeded 1 billion US dollars.

Alaska Pipeline The 800-mile trans-Alaska pipeline pumps oil from the northern coast to the southern border of Alaska. Construction started in 1973 and was completed 4 years later. The pipeline was originally budgeted $ 900 million, but the cost escalated to exceed $ 1 billion. A steel manufacturer was awarded the multimillion dollar contract to supply steel for the pipeline with S content of less than 0.005%. When several of the joint welds in the pipeline began to fail, it became clear that the S content was much higher than specified. The poor quality of the steel, in part due to inadequate or lack of measurements, set the project back several millions of dollars, once again emphasizing the need for accurate measurements. (Buskes and van Gerven) 9




Slide 10 The third, and final, example originates from the health sector. A detailed report in the USA showed that by reducing the uncertainty of cholesterol measurement from 24% to 5%, the USA economy saved, every year, 100 million US dollars. This arose from avoiding unnecessary treatment and improving the original diagnosis.

Cholesterol Measurements A high measurements uncertainty for cholesterol can lead to an unnecessary costly treatment or a higher health risk. Reducing the measurement uncertainty from 23.7% in 1949 to 5% in 1995, saves to the Unites States alone $ 100 million every year in health care costs. Standard reference materials played an important role in lowering the measurement uncertainty. (W. May) Note: Today other compounds (lipoproteins) are used for ris k markers of myocardial diseases 10




Slide 11 After these examples it should be clear now that measurements are very important with, amongst others, economic, political, social, environmental and scientific impacts.

Importance of Measurements

Economic Political Social Environmental Scientific 11




10


205

Slide 12 Today metrology is used by practically everybody. We see in this slide a list of the main users of metrology.

Measurements are used in

Industry (e.g. manufacturing) Commerce (e.g. disputes) Governments (e.g law implementation) Health and safety Environment protection Science / research Military services (e.g. navigation) Communications 12




Slide 13 Let’s see how metrology started! Before the 19th century, the measurement unit was something very unequivocal. In most cases the units depended very much on the ‘locality’ and very often were related to something that appeared to be constant like the king’s foot!

… Lack of Standard …

King’s foot

13




Slide 14 An interesting example was the length unit ‘ell’. This unit was used in many countries in Europe, but the actual length was different in different places.

… Lack of Standard … Variations of One Unit of Length (Ell) The “ell”, a unit originating from the custom of measuring cloth using one’s forearms, existed in many countries. In order to make trade possible at all in these days, conversion tables were used. (Buskes and van Gerven)

14




206


Slide 15 This table shows the length (in meters) of the unit ‘ell’ in different countries and cities in the middle ages.

… Lack of Standard … country England Scotland Germany Russia

ell(m) 1.14 0.94 0.6 0.5

city Vienna(A) Bruges (B) Amsterdam (NL)

ell(m) 0.78 0.70 0.69

(Buskes and van Gerven)

15




Slide 16 This lack of standards was resolved in the second half of the 19th century with the signature of the Meter Convention. This convention is a diplomatic treaty, which was signed in Paris (France) on 20th May 1875. This treaty establishes the International System of Units (SI) for the signatory countries. Currently 52 countries (all the major industrialized countries) have signed the treaty, and 36 countries are associate members.

Meter Convention

Diplomatic treaty 20th May 1875, in Paris SI system 52 signatory countries 36 associate members

16




Slide 17 The main aims of the Meter Convention are to achieve international uniformity of measurements of all kinds, establish a common system of units, achieve equivalent measurement standards in the members states, harmonize laws and regulations relative to measurements in the member states and achieve mutual recognition of measurements.

Meter Convention Aims

International uniformity in measurement Common system of units Equivalent measurement standards Harmonised laws and regulations Mutual recognition of measurements 17




10


207

Slide 18 As mentioned before, the SI is the major instrument of the meter convention.

SI International System of Units 18




Slide 19 The SI consists of seven base quantities from which all the other quantities (secondary or derived quantities) can be derived. The table in the slide presents the name of the quantities, their unit and the symbol of the unit.

SI Base Quantities

quantity unit symbol Length metre m Mass kilogram kg Time second s Electric current ampere A Thermodynamic temperature kelvin K Amount of substance mole mol Luminous intensity candela cd 19




Slide 20 Some examples of derived quantities are given in this slide. In particular the last one is widely used in analytical chemistry.

SI Derived Quantities Examples quantity Speed, velocity Density Concentration (of amount of substance)

unit symbol metre per second m/s kilogram per cubic metre kg/m3 mole per cubic metre mol/m3

20




208


Slide 21 What about chemistry and the SI? Chemistry is a quite new discipline for the SI. The quantity relevant to chemistry (i.e. the amount of substance) was adopted only in 1971, almost 100 years after the original signature of the meter convention. The unit of the amount of substance in the SI system is the mole (mol).

Chemistry in SI It is quite new!

Amount of substance (AoS) Agreed on 1971 Mole (mol) 21




Slide 22 What about traceability? Traceability of Length Traceability is the relationship of a Measurements result of a measurement to a value of a Length corresponding to X number of wavelengt hs of an I stabilized laser standard through an unbroken chain of comparisons (traceability chain). In value calibration 2 the case of the length measurements value calibration 1 this chain can be realized in the way tape measure value presented in the slide. When we want value to measure the length of a shark, the result of our measurement is dependent on the tape we are using (comparison). The scale of the tape depends on the calibration (comparison) of the production instrument and this depends on a number of other calibrations. The end of this ‘chain’ is the highest calibration, which is a comparison against the SI standard, in other words the realization of the meter. 2

22




Slide 23 There is often a misunderstanding related to traceability. It is often believed that the aim is traceability itself, but this is not true. The actual aim is to obtain comparable measurements in time and space. Traceability is just the best possible way to achieve this.

analytical measurements need to be comparable in time and space traceability is the best way to achieve this 23




10


209

Slide 24 Now let’s see how a traceability chain Traceability of can be realized for a chemical Chemical Measurements measurement. Generalizing and in an SI unit for amount of substance analogous way to length measurevalue ments it can be like the chain in the Reference Standard slide. The amount content of a value Working Standard compound X in a solution is compared with the amount content in a working amount content of X value compound in solution standard. This in turn was compared with the amount content in a reference standard and after some further comparisons, in an ideal situation we end up with the SI unit, the mole. Papadakis, I ., Magnusson, B.: Metrolog y in Chemi str y and Traceabi lit y In: W enclawiak, Koch, Hadj icostas (eds.)

24



Slide 25 This model of course makes a lot of assumptions and there are quite a few problems. It is not possible to have appropriate reference standards for all possible chemical measurements, very often there are no common links (i.e. reference to a common basis, which is ideally the SI), laboratories do not always use the standards in an appropriate way and very often the uncertainty concept is not used at all!

Problems... Absence of reference standards Absence of links to common basis Appropriate use of standards by laboratories Appropriate use of uncertainty 25




Slide 26 Before continuing, let’s see the official Traceability - Definition definition of traceability as given in the ISO international vocabulary of Metrological traceability basic and general terms in metrology. Property of a measurement result Traceability is defined as the property whereby the result can be related to a reference through a documented of the result of a measurement or the unbroken chain of calibrations, each value of a standard whereby it can be contributing to the measurement related to stated references, usually uncertainty (VIM, 3 edition) national or international standards, through an unbroken chain of comparisons all having stated uncertainties. rd


26



210


Slide 27 From the definition it can be concluded that the two major items at stake are the stated reference and stated uncertainties.

27




Slide 28 Various stated references are involved in a chemical measurement. In VIM the three different references possible are given with examples. For determining amount of substance several references can be involved e.g. we could weigh a material with known purity and from the known molar weight we could calculate the amount content. All the references used in a measurement should be stated and taken appropriately into account.

Stated References – 3 different In VIM 3 examples of different stated references are given A measurement unit (VIM 1.9), e.g. mol/l, °C A measurement standard (VIM 5.1), e.g. the certified reference material SRM 2193, a CaCO3 pH standard. A measurement procedure (VIM 2.6), e.g. ISO 1736:2008 Dried milk … - Determination of fat content. Determination of amount of substance requires in most cases measurements of different properties Sample mass Analyte identity Molar or Atomic weight

mass reference – meas urement unit pure material – meas urement standard published data or measured 28




Slide 29 The evidence required by the laboratory to demonstrate traceability for the mercury result is here given. Point 1 would need special attention to assure the quality and traceability for the calibration standard. Traceability for points 2, 3 and 6 is easily achieved with adequate uncertainty using commercial equipment. Points 4 and 5 need additional attention by the lab.

Several References for one measurand For measurements with more than one input quantity in the measurement model, each of the input quantity values should itself be metrologically traceable... NOTE 4 in VIM on Traceabil ity

Example: Mercury in tuna fish (with a AAS after microwave digestion) Measurement result: 4.03 ± 0.11 mg/kg, reported as total Hg on dry weight basis (105 ºC, 12 h) Traceability has to be demonstrated for: Mass concentration of the Hg solution 1.00 g/l Hg - a CRM certificate mass of sample 0.5 g - calibration certificat e of the balance volume of volumet ric flask 100 ml - calibration certific ate drying temperature 105°C - calibration of oven drying time 12 h - ordinary clock or stopwatch Microwave digestion conditions 0.5 h at 180 ºC - check according to specifications (from Eurachem Traceability leafl et – www.eurac hem.org) Papadakis, I ., Magnusson, B.: Metrolog y in Chemi str y and Traceabi lit y In: W enclawiak, Koch, Hadj icostas (eds.)

29



10


211

Slide 30 The case of the stated uncertainties is quite different. Uncertainty is the interval around the measurement results, which should contain the so-called ‘true value’. The uncertainty statement should always be accompanied by an uncertainty budget, which should include all uncertainties carried by all of the references used as well as the uncertainties introduced by the measurement process.

Stated Uncertainty An interval around the measurement result The uncertainty budget including: Uncertainties carried by the references Uncertainties introduced by the measurement process 30




Slide 31 In general the uncertainty contributions carried by the references are quite small compared to those, which originate from the measurement process.

Stated Uncertainty Usually the contribution of the uncertainties carried by the references to the total uncertainty is small relative the contributions that originate from the measurement process 31




Slide 32 As far as reference materials are concerned, the property values carried by reference materials, should be traceable to other references and in an analogous way the same features which are valid for the analytical laboratories, are also valid for the reference materials producers.

Reference Materials Values carried by reference materials should be traceable to other references The same features which are valid for the analytical laboratories are also valid for the reference materials producers

32




212


Slide 33 Detailed information relating to metrology in chemistry and traceability can be obtained from these web-sites. The addresses include international and regional organizations as well as some national metrology institutes.

More Information

www.bipm.org www.euramet.org www.citac.ws www.eurachem.org www.eurolab.org www.irmm.jrc.be www.nist.gov www.labnetwork.org 33




Slide 34 Summarizing this chapter, you must remember that metrology in chemistry is still a young discipline thus there is still a lot to be learned, traceability is not an aim by itself, but it is the way to achieve reliable and comparable results. Traceability can only be claimed when the uncertainty statement includes all the uncertainty contributions from the references and the measurement process.

Things to Remember Metrology in chemistry is still “young” There is a lot to learn Traceability is not an aim by itself but it helps achieving reliable results Traceability can only be claimed if uncertainty statement includes all the uncertainties from references and the measurement procedure 34




Bibliography Buskes H, v.Gerven B (1999) Footprint of the Meter. NMi Communicabus EURACHEM / CITAC (2008) Metrological Traceability of Analytical Results. Leaflet available from www.eurachem.org ISO/IEC Guide 99:2007 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM), 3rd edition, also available as JCGM 200:2008 from www.bipm.org Papadakis I, Wegscheider W (2000) CITAC Position Paper: Traceability in Chemical Measurement, Accred Qual. Assur 5:388-389

10


213

May W (1999) NIST SRMs. What they are, what they are NOT and their impact on the U.S. economy, international trade and quality of life. CITAC ’99 Japan Symposium on Practical Realization of Metrology in Chemistry for the 21th Century, Nov 9-11, Tsukuba, Japan

11 Validation of Analytical Methods – to be Fit for the Purpose

Bernd Wenclawiak and Evsevios Hadjicostas Fitness for purpose is the ultimate goal of the person doing the job in the laboratory, especially for the choice of method and instrumentation used to carry out an analysis. The validation of the analytical method is the important part to guarantee the fitness. This chapter aims to assist laboratories in implementing the principle that analytical measurements should be made using methods and equipment that have been tested to ensure they are fit for purpose. Slide 1 The following transparencies are a series of statements. Each emphasizes one part of the important role of analytical measurements. They go without saying to an analytical chemist. Satisfaction of requirements is scale of quality.

Analytical measurements should be made to satisfy an agreed requirement

1

W enclawiak, B., H adj icostas, E.: Valid ation of An alytical Methods – F it for the purpose © Springer-Verlag, Berlin Heidelberg 2010

Slide 2 This is the second one. If the method and the equipment are not fit for purpose there is no chance to deliver good quality.



Analytical measurements should be made using methods and equipment which have been tested to ensure they are fit for purpose

2

W enclawiak, B., H adj icostas, E.: Valid ation of An alytical Methods – F it for the purpose © Springer-Verlag, Berlin Heidelberg 2010 In: W enclawiak, Koch, Hadj icostas (eds.)



215

216


Slide 3 This is the third one. This statement is important. It refers to people. The staff doing the work have to be qualified and competent. This can be achieved by recruiting suitably qualified staff or by in service training. Competence arises from experience and training. A supervisor has to make sure that the staff are well trained and competent.

Staff making analytical measurements should be both: qualified and competent to undertake the task and demonstrate that they can perform the analysis properly Bild 1 3



Slide 4 This is the fourth statement. Laboratories must participate in regular independent assessments to demonstrate their technical performance.

There should be a regular independent assessment of the technical performance of a laboratory

4


Slide 5 This is the fifth statement. This implies, in many cases, that there must be an agreement on the method selected for the given analysis or, even better, the measurement is traceable to an agreed reference (see chapter 10).



Analytical measurements made in one location should be consistent with those made elsewhere

5



11

Validation of Analytical Methods – to be Fit for the Purpose

217

Slide 6 This is the sixth statement. Organizations making analytical measurements should have well defined quality control and quality assurance procedures. These procedures are explained in detail throughout this book.

Organizations making analytical measurements should have well defined quality control and quality assurance procedures

6



Slide 7 Validation is confirmation, through the provision of objective evidence that the requirements for a specific intended use or application have been fulfilled (ISO 9000:2005). Method Validation is therefore the process of confirmation that a method is fit-for-purpose, i.e. suitable for solving a particular analytical problem.

What is Method Validation? Method validation is an important requirement in the practice of chemical analysis Method validation is the process of proving that an analytical method is acceptable for its intended purpose Bild 2 7



Slide 8 This process consists of the establishment of the performance characteristics What is Method Validation? (e.g. precision, trueness, uncertainty) The process of establishing the performance and the limitations of the method (e.g. characteristics and limitations of a method and the identification of the influences which limit of detection, limit of quantification, may change these characteristics and to what working range). It is also important to extent. Which substances can it determine in which identify the influences that may matrices in the presence of which interferences? change these characteristics (e.g. inter Within these conditions what levels of fering substances, changes in the precision and accuracy can be achieved? sample matrix) and to what extend they might change them. Which analytes can be determined, in which matrices and in the presence of which interfering substances? Within these conditions: what levels of precision and accuracy can be achieved? Is the measurement uncertainty of the result acceptable for the intended use?



8

218


This process includes questions like: Is there a linear relationship between the signal and the concentration of the analyte? Are higher order terms required? Over what concentration range is this relationship valid? This means for example that the signal obtained from an instrument should only be the signal arising from the analyte, i.e. that there is no interference from other analytes present in the same sample/matrix. What precision and accuracy can be achieved? Just compare a simple photometric experiment with atomic absorption measurement and check for the effects from possible interferences. Slide 9 This is what analytical chemistry is all about, the selection from the methods that are available, the one which is most suitable for the task i.e. a method that is fit for purpose. For example you would probably never choose NMR for the determination of cations in water (ICP-OES or AAS are certainly more suitable).

The Method Validation Process Implies: The process of verifying that a method is fit for purpose, i.e. for use for solving a particular analytical problem This means the method must be suitable Method validation is not solely the process of evaluating the performance parameters

9



Slide 10 The Method Validation Process The equipment and instrumentation Implies: used for the determination of the Method performance parameters are performance parameters must be determined using equipment that is: within specification, Within specification Working correctly adequately calibrated and Adequately calibrated working correctly. Operator is fit for purpose Likewise the operator carrying out the Method validation and method development studies must be competent in the field of work under study and have sufficient knowledge related to such work to be able to make appropriate decisions. Such decisions are made after appropriate comparisons and statistical interpretation of the results. Many of the method performance parameters are usually evaluated as part of method development. It is for this reason that method validation is very closely related to method development. 10



11


219

Slide 11 The reason why method validation is Why is Method Validation necessary comes from the fact that Necessary? measurements are directly connected To increase the value of test results to activities of everyday life. The cost To justify customer’s trust of carrying out these measurements is To trace criminals high and additional costs –quite often To prove what we claim is true even higher - arise from decision made Examples To value goods for trade purposes on the basis of the results. Therefore it To support health care is necessary to have the confidence of To check the quality of drinking water the interested parties. It is for this reason that the performance parameters of the method are validated and the uncertainty of the results is evaluated at a predefined confidence level. It is to be noted that most of the information required to evaluate uncertainty can be obtained during the validation process or routine quality control (see chapter 12). 11



Slide 12 When performing laboratory work the The Professional Duty of the analytical chemist should know that Analytical Chemist the analytical results produced are not To increase reliability of laboratory results numerical figures with no further To increase trust of laboratory customers meaning. Most of the time the labora To prove the truth tory results have a considerable and multi-fold impact on everyday life. This impact affects the economic, social, juristic, welfare, environmental and many other interests of the laboratory’s customers. Therefore, the professional duty of the analytical chemist is to respect the interests of all the interested parties and to carry out his work with integrity in order to contribute effectively to the quality of life.

12



220


Slide 13 A method should be validated when it When should Methods be is necessary to verify that the performValidated? ance parameters are adequate for use New method development for a particular analytical problem. Revision of established methods or Method validation is required in instruments When established methods are used in circumstances such as those indicated different laboratories/different analysts etc. in this slide. QC indicates method changes Comparison of methods The extent to which method validation has to be decided by the laboratory, taking into consideration the time and cost to perform the validation on one hand and on the other hand the consequences that arise from a insufficient validation. The changes made in reapplying a method in different laboratories, with different instrumentation or operators, as well as changes made to meet customer requirements and relevant regulations, always have to be considered.

13



Slide 14 This is the main part of this chapter. Who? What? Why? How? Common questions in a new field.

How should Methods be Validated?

14


Slide 15


When a method is being developed, especially if it will be widely used, the validation is usually carried out by a group of laboratories. However, it is not always feasible for a laboratory to participate in or organize a collaborative study, since no other laboratory may be interested in taking part in a specific study. The competition between laboratories in the same or similar field of interest is also a constraint,



Who Carries out Method Validation? Validation in a single laboratory Comparisons with CRMs Comparisons with other methods that are validated

Validation in a group of laboratories Collaborative studies Inter-laboratory comparisons 15



11


221

that prevents laboratories from participating in such studies. In each case every laboratory has to investigate its performance factors such as linearity, interferences, or robustness. Where it is inconvenient or impossible for a laboratory to enter into a collaborative study it is possible to carry out method validation following internal procedures. In such cases, which are the most common, there is a need to provide objective evidence that the validation was carried out, using appropriate and approved methodology. The use of Certified Reference Materials or the comparison against a previously validated method is highly recommended in order for a validation to be recognized by regulatory or accreditation bodies. Slide 16 The customer gives the analytical laboratory information about the characteristics of the sample submitted for analysis. Such information should be, for example, the analyte to be measured, the expected concentration levels, which substances that might interfere with the determination of the analyte are present, how the sample was taken etc.


The Analytical Requirement (I)

What are the analytes of interest? What are the expected concentration levels? Are there any interferences? How was the sampling done?

16



Slide 17 How should Methods be Validated? Faced with an analytical problem, the laboratory, if necessary in collaboraThe Analytical Requirement (II) tion with the customer, evaluates exist Which method is the most suitable? ing methods for their suitability and What degree of validation is required? makes a decision on which method How will the method be used? probably is the most suitable, what degree of validation is required and how it will be used to solve the analytical problem in question. The decision, based on the results of the validation process, that the method is fit-forpurpose is usually left to the analyst’s discretion, who also decides what performance is required, what instruments and what facilities are to be used etc.

17



222


Slide 18 How should Methods be Validated? Method development can start with minor modifications on an existing Method Development method or may require the develop The one extreme: few sketchy ideas ment of a completely new one. If nec The other extreme: minor changes essary, the selected method for solving an analytical problem may need further development or validation of more performance characteristics. Method development can take a number of forms. The analytical chemist may start out with a few sketchy ideas and apply expertise and experience to devise a suitable method or he/she may adapt existing methods making minor changes so that the method is suitable for a new application.

18



Slide 19 How should Methods be Validated? As a general rule, it is necessary for a Deciding what Degree of laboratory to be able to have an Validation is Required adequate level of confidence in the Time and cost constraints results produced; otherwise the work Customers’ requirements is not worth doing. The validation of a Existing experience method usually is costly and time Compatibility with other similar methods consuming and in some cases it may be more appropriate to subcontract the work to another laboratory instead of installing a new method. If possible the customer should be involved in the decision on the degree of validation required. The knowledge of the laboratory about the performance of the method to be used as well as any data showing compatibility of the method in question with similar methods helps to decide the degree of validation required.

19



11


223

Slide 20 Being familiar with a method ensures Rules Recommended to Ensure acceptable performance. New operators, Acceptable Performance this might include newcomers to a job Analyst should be familiar with method before or students or other trainees, need using it for the first time Work firstly under supervision training before performing the job on Get training their own. First the trainee studies the Think ahead of process, solutions etc. required Make an assessment how many samples can instructions and handouts provided. be handled at a time He has to familiarise himself with Make sure everything needed is available before work starts the theory behind the measurement. The trainer/supervisor demonstrates the method while the trainee is watching. After this the trainee uses the method under supervision with material analysed before, e.g. in-house reference material. Can he achieve the performance stated in the method? He has to learn to think ahead, making sure that all material/solutions are ready when required. The assessment should give information on how many samples can be handled at a time. Standards, reagents, and equipment (and sometimes bench space) should be available before the work starts.

20



Slide 21 How should Methods be Validated? The effort required to get the necesDeciding what Degree of sary information can be minimized Validation is Required with careful planning. This is because Category of the method Action necessary a particular set of experiments often Interlaboratory tested Precision, trueness Interlaboratory tested but it applies with Precision, trueness, limit yields information on several paradifferent material, different instrument of detection, selectivity Established but not tested Many meters. Some of the parameters may From bibliography, with reference to Many have been determined during the performance characteristics From bibliography, without reference to Many method development stage. The laboperformance characteristics In-house method Full validation ratory makes the appropriate decision as to the degree of validation required taking into account the customer’s requirements, existing experience in the use of the method and the need for compatibility with other similar methods already in use within the laboratory or being used by other laboratories.

21



224


Slide 22 How should Methods be Validated? The laboratory should agree with the Choosing, Developing and Evaluating Methods customer which requirements with respect to analysis and performance the method must have. Is an existing method suitable or must a new method be developed? Evaluation and development of a new method are a continuing process which is best explained in the End depiction given here. This figure has been taken from the “The Fitness for Purpose of Analytical Methods: A Laboratory Guide to Method Validation and Related Topics” (1998) published by EURACHEM. Problem requiring chemical analysis: Set analytical requirement

Dev elop method

Y es

Identify existing method or dev elop new method

Method validati on c onsists of t his evaluation stage, together with any perfor manc e parameters that may be evaluated under method devel opment „Fit for purpose...“ . R egardless of what existing perf ormance data may be available for the method, fitness f or purpos e will be det ermined by how t he met hod performs when us ed by the designat ed anal yst with the available equipment/f acilities.

Ev aluate method – f it f or purpose as used in the laboratory

No

Further dev elopment f easible?

Y es

No

Relax analy tical requirement ? No

Y es

Analy tical work proceeds

Unable to do work – subcontract?

Analy tical requirement re-stated in terms of what has been accomplished

Taken from Eur achem guide „Fitness for Purpos e“

22



Slide 23 How should Methods be Validated? If the signal can be attributed only to The Different Performance Parameters of a the analyte identity is confirmed. Method and what they Show - what to Check Selectivity is important, if interferences Confirmation of identity Bias interpretation are present. For example a reference and selectivity Precision compound and an analyte compound Limit of detection Repeatability Limit of quantification generate a peak in a chromatogram at Reproducibility Working and linear Sensitivity the same retention time. Either ranges Ruggedness or columns of different polarity or a mass Accuracy robustness Trueness Recovery spectrometer as detector can help to identify a single compound peak. Limit of Detection (LoD) is the lowest concentration that can be detected with specified confidence for a specific substance. Limit of Quantification (LoQ) is the minimum content that can be quantified with a certain confidence. Values below LoQ are reported as less than (see also chapter 9). Accuracy is the closeness of a result to a true value and combines precision and trueness. Trueness is the closeness of agreement between the average value obtained from a large set of test results and an accepted reference value. The measurement bias is an estimate of a systematic measurement error. Precision is the closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions.

23



11


225

Repeatability means conditions of measurement that includes the same measurement procedure, same operators, same measuring system, same operating conditions and same location, and replicate measurements on the same or similar objects over a short period of time. Reproducibility means conditions of measurement that includes different locations, operators, measuring systems, and replicate measurements on the same or similar objects. Sensitivity of a measuring system is the quotient of the change in an indication of a measuring system and the corresponding change in a value of a quantity being measured. Robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate variations. Recovery is the fraction from an analyte added to a test sample (fortified or spiked sample) prior to analysis that finally was found with the analysis. The percentage recovery (%R) is calculated as %R = [(CF-CU)/CA] x 100, where CF is the concentration of analyte measured in the fortified sample, CU is the concentration of analyte measured in the unfortified sample and CA is the concentration of analyte added [AOAC-PVMC]. Slide 24 During the analysis process there is the How should Methods be Validated? stage of measuring the signal Identity and Selectivity attributed to the analyte. The analytical Identity: Signal to be attributed to the analyte chemist must prove whether this signal e.g. GC (use two differently coated columns), corresponds to the analyte or whether GC-MS and GC-IR (use two different detectors) Selectivity: The ability of the method to part of it is to be attributed to interfering determine accurately the analyte of interest in impurities. This is the confirmation of the presence of other components in a sample matrix under the stated conditions of identity. Selectivity is a measure that the test. assesses the reliability of measurements in the presence of interferences. The Selectivity of a method refers to the extent to which it can determine particular analyte(s) in a complex mixture without interference from the other components in the mixture. The term specificity was used in the past to describe complete selectivity. Due to the fact that perfect selectivity can never be reached, IUPAC recommends, not to use this term. 24



226


Slide 25 Confirmation increases confidence in the technique under examination and is especially useful when the confirmation techniques operate on significantly different principles. It is essential to distinguish between the meanings of repeatability and confirmation. Whereas repeatability requires the measurement to be performed several times by one technique, confirmation requires the measurement to be performed by more than one technique.


Identity and Selectivity Confirmation versus repeatability Confirmation: Measure by more than one technique Repeatability: Measure several times by one technique

25



Slide 26 How should Methods be Validated? The selectivity of the method is usually investigated by studying its Identity and Selectivity ability to measure the analyte of interest How to establish selectivity: in test portions to which specific interferences have been deliberately Compare the response of the analyte in a test mixture with the response of a solution introduced (those thought likely to be containing only the analyte. present in samples). Where it is unclear whether or not interferences are already present, the selectivity of the method can be investigated by studying its ability to measure the analyte by comparison with other independent methods or techniques.

26



Slide 27 The procedure to establish selectivity of the method is the following: Analyse samples and reference materials by the candidate and other independent methods. Assess the ability of the methods to confirm analyte identity and their ability to measure the analyte in isolation from the interferences.


Identity and Selectivity The procedure to establish selectivity: Analyze samples and reference materials Assess the ability of the methods to confirm identity and measure the analyte Choose the more appropriate method. Analyse samples Examine the effect of interferences 27



11 -


227

Choose the most appropriate method. Analyse samples containing various suspected interferences in the presence of the analyte of interest. Examine the effect of interferences and decide whether further method development is required.

Slide 28 How should Methods be Validated? Where measurements are made at low concentration levels, e.g. in trace Limit of Detection (LoD) analysis, it is important to know what LoD:The lowest concentration of analyte is the lowest concentration of the in a sample that can be detected with a analyte that can be confidently detected certain level of confidence by the method. For validation purposes LoD = B + 3 s or 0 + 3 s (for fortified samples) (typically, three times the noise level) it is normally sufficient to provide an B=Blank s =standard deviation of 10 measurements indication of the level at which detection becomes problematic. Limit of detection is the lowest concentration of analyte in a sample that can be detected, but not necessarily quantified under the stated conditions of the test. 0

0

0

28



Slide 29 The Limit of Detection is expressed as How should Methods be Validated? the concentration or the quantity Expression of the LoD derived from the smallest signal that can Analyse be detected with reasonable certainty 10 independent sample blanks and get the mean sample blank value (B) or for a given analytical procedure. One 10 independent sample blanks fortified at lowest acceptable concentration. possibility to express the LoD is as the Express LoD as the analyte concentration mean blank value plus three times the corresponding to B + 3 s or standard deviation of 10 measurements 0+3s of the blank sample (see also chapter 9). (s being the sample standard deviation). In the case where a blank sample does not produce a measurable signal, fortified samples on a very low level have to be used.

29



228


Slide 30 How should Methods be Validated? Limit of Quantification (LoQ) is the lowest concentration of analyte in a Limit of Quantification (LoQ) sample that can be determined with The Limit of Quantification is the acceptable accuracy, i.e. with acceptminimum content that can be quantified able precision and acceptable trueness, with a certain confidence The lowest concentration point on the under the stated conditions of the test. calibration curve should not be below It is an indicative value and should not the LoQ LoQ = B + 10 s0 normally be used for decision-making Bild 4 purposes. It should be established using an appropriate measurement standard or sample and should not be determined by extrapolation. The LoQ is calculated as the analyte concentration corresponding to the sample blank value plus 10 standard deviations of the blank measurement. If measurements are made under repeatability conditions, a measure of the repeatability precision at this concentration is also obtained. 30



Slide 31 How should Methods be Validated? The calculation of the Limit of DetecLimit of Detection (LoD) tion and/or Limit of Quantification can Limit of Quantification (LoQ) also be made using a graphical Graphical method method. In this case the analyst Six measurements in 3 concentration levels prepares at least three test samples at Std.dev. for each one level s = f(c) different concentration levels and s = intercept makes at least six measurements at LoD = 3 s Signal to Noise ratio S/N = 3 (for the LoD) each concentration and calculates the Signal to Noise ratio S/N = 10 (for the LoQ) mean concentration c and standard See also chapter Glossary deviation s. The three mean concentration values are the independent variables and are plotted on the X-axis against the corresponding s values which are the dependant variables plotted on the Y–axis. s0 is the intercept at the Y-axis and LoD = 3 S0 whilst LoQ is 10 S0. For more background on the determination of LoD and LoQ see chapter 9. 0

0

31



11


229

Slide 32 Linearity is the ability of the method to How should Methods be Validated? obtain measuring signals proportional Linearity and Working Range to the concentration of the analyte. Linearity Linear range is by inference the range The ability of the method to obtain measuring of analyte concentrations over which signals which are proportional to the concentration of the analyte the method gives signals proportional to the concentration of the analyte. For any quantitative method it is necessary to determine the range of analyte See also chapter Glossary concentrations over which the method may be applied. At the lower end of the concentration range the limiting factors are the values of the limits of detection and quantification. At the upper end of the concentration range various effects, depending on the response of the instrument system, will impose limitations. 32


Slide 33



Linearity and Working Range The working range is limited by the lowest and the highest calibration Working Range Limited by the lowest and the highest calibration point. The lowest one should not be point below the LoQ. Within the working A linear calibration curve can only be used if linearity over the working range is ensured range there may exist a linear response Coefficient r is a measure of correlation, not a range within which the signal response measure of linearity Check graphical display of calibration data and/or will have a linear relationship to the residues analyte concentration. Linearity for quantitative methods is determined by the measurement of samples with analyte concentrations spanning the claimed range of the method. The results are used to calculate a regression line against analyte calculation using the least squares method. Different criteria are used to establish good correlation of the concentration with signal. The coefficient r is a measure of correlation not a measure of linearity! Linearity can be checked by determining the signal to concentration ratio. A range below 5% of the averaged signal to concentration ratio is considered linear. Plotting the calibration range can reveal the results better than any mere calculation. Evaluation of the working and linear ranges will also be useful for planning the degree of calibration required when using the method on a day-to-day basis. Within the linear range, one calibration point is sufficient to establish the slope of the calibration line whereas a multi-point calibration is required when working elsewhere in the working range. In general linearity checks require points at at least 10 different concentrations/property values.

33



230


Slide 34 Accuracy expresses the closeness of a How should Methods be Validated? result to the true value. Accuracy = Accuracy/Trueness/Precision trueness + precision. Under specific conditions it is quantified by the Accuracy: Closeness of agreement between a measured quantity value and a true quantity value of a measurand measurement uncertainty. Measure[VIM] Trueness: The closeness of agreement between the ment uncertainty may vary under average of a infinite number of replicate measure quantity values and a reference quantity value [VIM] changing conditions and method Precision: closeness of agreement between indications validation determines the degree. or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions [VIM] Method validation seeks to quantify the likely accuracy of results by assessing both systematic and random effects on results. The property related to systematic errors is the trueness, i.e. the closeness of agreement between the average value obtained from a large set of test results and an accepted reference value. The property related to random errors is precision, i.e. the closeness of agreement between independent test results obtained under stipulated conditions. Accuracy is therefore, normally studied as trueness and precision.

34



Slide 35 A result could have “good precision” but a “bad trueness”. That is, all measurements could be repeatable, but the mean value could be far away from the true value. This is not a “good accuracy”. Similarly, a result could have “good trueness” whilst precision could be bad. In this case the mean value may be close to the true value even though precision is low. This is again not a “good accuracy”. See also chapter 8 for further information.

How should Methods be Validated? Good Trueness Good Precision

Bad Trueness Good Precision

Good Trueness Bad Precision See also graphics slide 36 in chapter Basic Statistics

35



11


231

Slide 36 How should Methods be Validated? Trueness is assessed against a reference value (i.e. a conventional true Determination of Trueness value). Trueness is a property related Using Certified Reference Materials to systematic errors. Using RM or In-house materials Two basic techniques are available: Using Reference methods checking against reference values Single sample from a characterized material or Many samples from a characterized method. Via Interlaboratory study Via recovery study Certified Reference Materials (CRM) should provide traceable values (to international standards), which are the “reference values”. Trueness can also be studied via interlaboratory studies as well as by using recovery study on spiked samples and calculating the recovery. The possibilities stated in the slide are hierarchically sorted, i.e. the top methods are usually regarded as the most reliable ones. 36



Slide 37 How should Methods be Validated? To check trueness using a reference material, a series of replicate tests is Determination of Trueness carried out and the mean value and Using Certified Reference Materials standard deviation are compared with A 1-sample-t-test can be applied the characterized value for the refer Perform some analyses (e.g. at least five*), ence material. Certified matrix referthen calculate the confidence interval of the arithmetic mean and check if the ence materials may be purchased and reference value is within this interval used directly for validation. If this is t t x− ⋅s 〈 x 〈 x+ ⋅s n n not possible reference materials for validation may be prepared by spiking typical materials with pure Certified Reference Materials or other materials of suitable purity and stability. In-house reference materials may be prepared from typical, well-characterized materials checked in-house for stability and retained for in-house Quality Control. The trueness is determined by comparing the arithmetic mean, x , of the value that the laboratory assigns to the Certified Reference Material with the reference value xref of the CRM, which is (by definition) accepted as sufficiently true. If it is found to be within the confidence interval of the laboratory’s results, then this is judged to be a satisfactory outcome. ref

*

NORDTEST Handbook

37



232


Slide 38 How should Methods be Validated? For the evaluation of the significance test usually the tobserved-value is Determination of Trueness x−x calculated as shown in the slide and = The formula can be re-arranged: t s compared with the critical value from n To be exact we also have to include the statistical tables for the required uncertainty of the reference value and get: x−x t = confidence level. For more details on ⎛s ⎞ +u ⎜ ⎟ n⎠ ⎝ significance testing see chapter 8 on Compare tobserved with tcritical from statistical ‘Basic Statistics’. tables for the required level of confidence If tobserved < tcritical, there is no significant If a Reference Material (RM), without difference a certified value or if an in-house material is used, there is no certified, traceable value. However, the procedure is the same. The value assigned to the material by the laboratory itself is the best available estimate for the ‘true’ value. Of course the determination of trueness is not as reliable as with a CRM.

ref

observed

ref

observed

2

2 ref

38



Slide 39 How should Methods be Validated?

To check trueness against an alternative Determination of Trueness method, the same sample or samples Using reference methods and one sample are analysed by the two methods and In this case a 2-sample-t-test may be applied Analyse the same sample several times with the two series of results are compared both methods (X and Y) for a statistically significant differx−y s t ≤ s ( N − 1) + s ( N − 1) ence. The samples may be CRM’s, F = ,s > s 1 1 s = s × + s N + N −2 N N in-house standards, or simply typical 99% They also can be characterised by facturer or a calibration laboratory. standard deviations In some cases the only available information is the analyst’s experience. In the latter case the only thing possible is a qualified guess. We have to find the best way how to convert the available knowledge into a standard uncertainty. All these types of estimation are called type B evaluation. Koch, M.: Measur ement Uncertaint y

24




Slide 25 From the above mentioned estimation process we get the standard uncertainty of the parameter influencing the result. But we are interested in the component of the uncertainty of the result caused by that parameter. So we have to convert the first one into the latter one. This is done by multiplying the uncertainty of the parameter with a sensitivity coefficient which can be obtained from the partial derivation of the result with respect to the respective parameter.

The Uncertainty Estimation Process Step 4 Conversion of the uncertainty of a parameter into an uncertainty component of the result The extend to which the uncertainty of the result is influenced by this parameter is reflected by the “quantitative expression” determined in step 1. The related sensitivity coefficient is determined by partial derivation of y with respect to our parameter xi u ( y , x i ) = c i ⋅ u( x i ) =

∂y ⋅ u( xi ) ∂x i

u(y,xi) denotes the uncertainty in y arising from the uncertainty in xi 25

Koch, M.: Measur ement Uncertaint y In: W enclawiak, Koch, Hadj icostas (eds.)


12

Measurement Uncertainty

257

Slide 26 The combined uncertainty we get from the square root of the sum of squares of all uncertainty contributions.

The Uncertainty Estimation Process Step 4 Calculation of Combined Uncertainty The general relationship between the combined standard uncertainty uc(y) of a value y and the uncertainty arising from the independent parameters x1, x2, ...xn on which it depends is according to the law of propagation of errors uc ( y ( x1, x 2 ,...)) =

n

∑ u( y , x ) i =1

2

i

26

Koch, M.: Measur ement Uncertaint y

Slide 27 The last step is the calculation of the uncertainty with a higher level of confidence, the expanded uncertainty. As described above this is done by multiplying with a coverage factor k.



The Uncertainty Estimation Process Step 4 Calculation of Expanded Uncertainty The combined uncertainty is multiplied with the coverage factor

U = k ⋅ uc

A coverage factor of 2 delivers a confidence level of about 95% 27


Slide 28 As already mentioned the modelling approach described in the GUM is difficult to translate into analytical chemistry because the testing procedures are very complex and it is a huge effort to identify and quantify all uncertainty sources. For routine laboratories often handling dozens or even hundreds of different test methods it is nearly impossible to cope that with the modelling approach.



Problems in Chemical Laboratories Chemical analyses often are very complex testing procedures with lots of uncertainty sources that can hardly be quantified separately The calculation of a complete uncertainty budget for all routine tests often is impossible for chemical laboratories 28



258


Slide 29 Having this in mind other approaches were developed that use already existing quality control and validation data. One of the most widely known publication for that is the NORDTEST “Handbook for calculation of measurement uncertainty in environmental laboratories”.

NORDTEST Handbook NORDTEST, a cooperation of laboratories in the Nordic countries, published a „Handbook for calculation of measurement uncertainty in environmental laboratories” To provide a practical, understandable and common way of measurement uncertainty calculations, mainly based on already existing quality control and validation data covering all uncertainty sources in a integral way Available as TR 537 from: www.nordicinnovation.net/nordtest.cfm 29


Slide 30 The Handbook describes two possibilities where one is using quality control and validation data with the aim to come up with data for the imprecision (lack of precision) and for bias (lack of trueness). The other method uses data from interlaboratory tests directly.



NORDTEST-Approach – 2 possibilities a) Combination of

Reproducibility within the laboratory and Estimation of the method and laboratory bias

b) Use of reproducibility between laboratories more or less directly (as described also in ISO/TS 21748:2004) 30


Slide 31



This flowchart is describing the whole Flowchart for Method a) process divided in 6 steps: 1. Specification of the measurand (as described above) 2. Quantification of the within laboratory reproducibility (or better the imprecision) 3. Quantification of the laboratory and method bias 4. Conversion into standard uncertainties 5. Calculation of the combined uncertainty 6. Calculation of the expanded uncertainty Specify measurand

Q bility Q uantify uantify components components for for w w ithin ithin lab lab reproduci reproducibility AA control control samples samples BB possible possible steps, steps, not not cov cov ered ered by by the the control control sample sample

Q Q uantify uantify bias bias components components

CC onvert onvert components components to to standa standa rd rd unce uncertainty rtainty

CC alculate alculate combined combined standard standard unce uncertainty rtainty

u1

u1 + u 2

u2

CC alculate alculate expanded expanded uncertainty uncertainty U U= = 22 ⋅⋅ uucc





12


259

Slide 32 We are starting with the case where Reproducibility within the Laboratory Rw we have a control sample that covers Control Sample Covering the Whole Analytical Process If the whole analytical process including The control sample covers the whole analytical process and Has a matrix similar to the samples, all sample preparation steps. The The within-laboratory reproducibility at that concentration level can simply be estimated from the analyses of the control sample matrix of the control sample is similar If the analyses performed cover a wide range of concentration levels, also control samples of other concent ration levels should to that of the routine samples. Then the be used. standard deviation of the analysis of Reproducibility within the lab R this sample (under between-batch conditions) can be used directly as an estimate for the reproducibility within the laboratory. The standard deviation can be taken directly from a control chart for this control sample (see chapter13). In the table two examples are shown for different concentration levels. val ue

rel. Uncertaint y

Comments

w

Control sampl e 1 x = 20. 01 µg/l

sR w

standard deviation 0.5 µg/l

2.5 %

from 75 measurements in 2002

Control sampl e 2 x = 250.3 µg/l

sR w

standard deviation 3.7 µg/l

1.5 %

from 50 measurements in 2002

Other c omponents

---


32




Slide 33 If we don’t have such an ideal control Reproducibility within the Laboratory Rw sample, but only one with a matrix Control Samples for Different Matrices and Concentrations If different from the routine sample (e.g. A synthetic control solution is used for quality control, and The matrix type of the control sample is not similar to the natural a standard solution) than we have to samples We have to take into consideration uncertainties arising from consider also the uncertainty compodifferent matrices These can be estimated from the repeatability with different nent arising from changes in the matrices (range control chart) matrix. For this purpose we use the Reproducibility within the lab R (repeatability) standard deviation calculated from repeated measureNote: The repeatability component is included twice!! ments of our routine samples (performed e.g. for a range control chart). When we estimate the reproducibility within laboratory we now have to combine both contributions by calculating the square root of the sum of squares. In the table we have again two examples, one using absolute values (because we assume the absolute uncertainty to be nearly constant in this concentration range) and one using relative values (because we assume that the relative uncertainty is more constant for higher concentrations). The repeatability of the analysis is included in both components. We accept this (usually small) incorrectness in order to keep it simple. u(x)

Comments

Low level (2-15 µg/l)

sRw

0.5 µg/l from the mean c ontr ol chart 0.37 µg/l from the range c ontrol c hart

val ue

0.6 µg/l

Absolute: u(x)=(0.5² + 0.37²) 1/2

High level

sRw

1.5 % from t he mean c ontrol chart

3.9 %

Relative:

w

(>15 µg/l)

3.6 % from t he range control chart

u(x)=(1.5%² + 3.6%²) 1/2

33





260


Slide 34 In some cases it is completely imposReproducibility within the Laboratory Rw Unstable Control Samples sible to prepare control samples for the If The laboratory does not have access to stable control samples (e.g. use in X-charts. So we have only the measurement of dissolved oxygen) It is possible only to estimate uncertainty components from second component from the last repeatability via the range control chart The „long-term“ uncertainty component (from batch to batch) has example. The long-term component to be estimated e.g. by a qualified guess that takes into account changes Reproducibility within the laboratory R between series has to be estimated differently. If we don’t have other data, the last possibility is a qualified guess based on the experience of the analyst. In the table an example is shown where the analyst expects the between-series standard deviation in the range of about 0.5% based on observations during the calibration of the oxygen sensor. val ue

u(x)

Comments

s = 0.024 mg/l mean: 7. 53 mg/l

0.32 %

from 50 measurements

s = 0.5 %

0.5 %

based on experience

w

Duplicate measurements of natural samples

Estimated variation from differ ences in calibration over time

Combined unc ertaint y for Rw Repeatability + Reproducibility in calibration



sr

0.32 % 2 + 0.5% 2 = 0.59 %

34



Slide 35 After the (im)precision part of the Method and Laboratory Bias uncertainty we now want to estimate Can be estimated from the trueness (bias) part. For that we The analysis of certified reference materials The participation in proficiency tests use either the results of the analysis of From recovery experiments Sources of bias should always be eliminated if certified reference materials, the results possible of our participation in proficiency tests According to GUM a measurement result should always be corrected if the bias is significant and or recovery experiments. The first based on reliable data such as a CRM. In many cases the bias can vary depending on choice is always to eliminate systemchanges in the matrix. This can be reflected when atic deviations. The second choice is, analysing several matrix CRMs to correct the measurement result for that deviation, if it is constant and we have reliable information on it. If both are not possible we include the bias component in our measurement uncertainty estimate. Koch, M.: Measur ement Uncertaint y


35



12


261

Slide 36 The bias part of the uncertainty also has two parts: the bias itself and the uncertainty of the nominal value. If only one certified reference material is available we have to include the uncertainty of the determination of the bias in addition. This is done by using the standard deviation of this bias determination. All components are combined as shown in the slide.

Method and Laboratory Bias ubia s Components of Uncertainty The bias (as % difference from the nominal or certified value) The uncertainty of the nominal/certified value u(Cref ) ubias can be estimated by: 2 ubias = RMSbias + u(Cref )2

with

RMSbias =

∑ (bias )

2

i

n

And if only one CRM is used 2

⎛s ⎞ ubias = (bias)2 + ⎜ bias ⎟ + u(Cref )2 ⎝ n ⎠ 36





Slide 37 We start with an example where only one certified reference material is available with a certified value of 11.5 and an expanded uncertainty (95%) of 0.5. First we convert the expanded uncertainty into a standard uncertainty by dividing it by 1.96. Now we have the standard uncertainty of the reference value.

Method and Laboratory Bias ubia s Use of One Certified Reference Material The reference material should be analysed in at least 5 different analytical series Example: Certified value: 11.5 ± 0.5 (95% confidence interval) Uncertainty component from the uncertainty of the certified value Conv ert the conf idence interv al

The conf idence interv al is ± 0.5. Divide this by 1.96 to conv ert it to standard uncertainty : 0.5/1.96=0.26

Conv ert to relativ e uncertainty u(C ref )

100⋅(0.26/11.5)=2.21 %

37





Slide 38 The next step is the quantification of the bias itself from the mean of the results of analysis of the CRM and the standard deviation of these measurements. Using the formula from slide 36 and the uncertainty of the reference value from the previous slide we get the bias uncertainty component.

Method and Laboratory Bias ubia s Use of One Certified Reference Material Quantify the bias The CRM was analysed 12 times. The mean is 11.9 with a standard deviation of 2.2% This results in: bias = 100 · (11.9 – 11.5) / 11.5 = 3.48% and s bias = 2.2% with n = 12 Therefore the standard uncert ainty is: 2

⎛s ⎞ ubias = (bias)2 + ⎜ bias ⎟ + u(Cref )2 = ⎝ n ⎠ 2

⎛ 2.2% ⎞ (3.48%)2 + ⎜ ⎟ + 2.21%2 = 4.2% ⎝ 12 ⎠ 38



262


Slide 39 If we are lucky and we have several CRMs available, the uncertainty of the bias determination is covered by the results of the measurement of the different materials. From the biases of each CRM analysis we calculate the root of the mean of squares as shown in the slide. Finally we combine this value with an average of the uncertainty of the certified value and we get the final uncertainty component.

Method and Laboratory Bias ubia s Use of Several Certified Reference Materials Quantification of the bias

Bias CRM1 is 3.48%, s=2.2% (n=12), u(Cref)=2.21% Bias CRM2 is –0.9%, s=2.0% (n=7), u(Cref)=1.8% Bias CRM3 is 2.4%, s=2.8% (n=10), u(Cref)=1.8% RMSbias then is:

RMSbias =

∑ (bias ) i

n

2

=

3.48%2 + ( −0.9%)2 + 2.4%2 = 2.5% 3

And the mean uncertainty of the certified value u(C ref): 1.9% This results in the total standard uncertainty of the bias: 2 ubias = RMSbias + u(Cref )2 = 2.5%2 + 1.9%2 = 3.1%

39



Slide 40 If no CRM is available at all, but we Method and Laboratory Bias ubia s participated in a proficiency testing Use of PT Results scheme, we can use these results also In order to have a reasonably clear picture of the bias from interlaboratory comparison results, a for the estimation of the bias uncertainty laboratory should participate at least 6 times within a reasonable time interval component, provided that we assume Uncertainty component from the uncertainty of the nominal value the assigned value in the PT to be a good estimate for the true value. Of course one PT participation is not enough. At least six PT participations are recommended. Again we have to quantify the uncertainty of the nominal value (i.e. the assigned value in the PT) and the bias itself. Sometimes the uncertainty of the assigned value is delivered by the PT provider. If not, the uncertainty of a consensus mean can be estimated from the reproducibility standard deviation and the number of participants as shown in the slide. Between labo ratory standard dev iations s R

s R has been on av erage 9% in the 6 exercises

Conv ert to relativ e uncertainty u(C ref )

Mean number of participants= 12

u(Cref ) =

sR 9% = = 2 .6 % n 12

40





12


263

Slide 41 For the calculation of the bias itself we again use the root of the mean of squares of all biases. In the example shown we have 6 PT results. We calculate the relative bias of these values and then the RMSbias. Finally we combine the RMSbias with the uncertainty of the assigned value and we get the uncertainty component for the bias.

Method and Laboratory Bias ubia s Use of PT Results Quantification of the bias In the 6 participations the differences between the lab results and the assigned value biases have been: 2%, 7%, -2%, 3%, 6% and 5% Therefore RMSbias is: RMS bias =

∑ (bias )

2

i

n

=

2%2 + 7%2 + ( −2%)2 + 3% 2 + 6%2 + 5%2 = 4.6% 6

And the total standard uncertainty of the bias: 2 ubias = RMSbias + u(Cref )2 = 4.6%2 + 2.6%2 = 5.3%

41



Slide 42 A third possibility to estimate the bias Method and Laboratory Bias ubia s From Recovery Tests component of the uncertainty is to per Recovery tests, for example the recovery of a standard addition to a sample in the validation process, can be used to estimate the form a recovery experiment, where a systematic error. In this way, validation data can provide a valuable input to the estimation of the uncertainty. sample is spiked with the analyte. The Example: In an experiment the recoveries for an added spike were 95 %, 98 %, 97 %, 96 %, 99 % and 96 % for 6 different sample matrices. The spike of 0.5 ml was added with a micropipette. uncertainty of the nominal value (i.e. the spiked amount) has to be calculated from the uncertainty of the volume added and the concentration of the spike solution. In the example in the slide the spiking is done using a micropipette. The uncertainty of the concentration of the spike solution is taken from the certificate of the manufacturer of the standard solution used and the uncertainty (repeatability and max. bias) of the micropipette is delivered by the respective manufacturer. Both components are combined to the uncertainty of the spike. uncertainty component from spiking Uncertainty of the concentration of the spike u(conc)

f rom the certif icate: 95% conf idence interv all = ± 1.2 % u(conc) = 0.6 %

Uncertainty of the added v olume u(v ol)

f rom the manuf acturer of the micro pipette: max. bias: 1% (rectangular interv al), repeatability : max. 0.5% (standard dev.) 2

⎛ 1% ⎞ u(vol ) = ⎜ ⎟ + 0.5%2 = 0.76 % ⎝ 3⎠

Uncertainty of the spike u(c recovery)

u(conc )2 + u(vol )2 = 0.6%2 + 0.76 %2 = 1.0%

42





Slide 43 Now we quantify the bias itself in the same way as above. We calculate the RMSbias of the bias (100% - recovery). Finally we combine the two contribution and we get ubias.

Method and Laboratory Bias ubia s From Recovery Tests Quantification of the bias: RMSbias : RMS bias =

5 % 2 + 2% 2 + 3% 2 + 4% 2 + 1% 2 + 4% 2 = 3.44% 6

Therefore the total standard uncertainty of the bias is: 2 ubias = RMSbias + u(Cre cov ery )2 = 3.44%2 + 1.0%2 = 3.6%

43



264


Slide 44 In the last slides we got to know different possibilities to estimate Rw as well as ubias. To get the overall combined standard uncertainty uc of our analyses we again combine these contributions as root of the sum of squares.

Combination of the Uncertainties (Reproducibility within the Laboratory and Bias)

Reproducibility (Rw) (from control samples and other estimations)

Bias ubias (from CRM, PT or recovery tests) Combination: 2

uc = u(Rw )2 + ub ias

44


Slide 45 To get an expanded uncertainty with a higher level of confidence we multiply the combined standard uncertainty with a coverage factor k. If we choose k=2, we get a confidence level of approximately 95%.



Calculation of the Expanded Uncertainty For the conversion to an approx. 95% confidence level

U = 2 ⋅ uc 45


Slide 46



If we fail with the method described Method b) - Direct Use of above because of lack of data or for Reproducibility Standard Deviations other reasons, we also have the If the demand on uncertainty is low possibility to use the reproducibility uc = sR standard deviation taken from an inter The expanded uncertainty becomes U = 2 ⋅ sR laboratory comparison, which was This may be an overestimate depending on either performed for the validation of the quality of the laboratory – worst-case scenario the method (e.g. during standardization) It may also be an underestimate due to sample inhomogeneity or matrix variations or for proficiency testing of laboratories (see also ISO/TS 21748). Usually this method is applicable only if the demand on uncertainty is low. We simply set uc = sR and therefore we get U = 2 · sR. Depending on the quality of the laboratory compared with those participating in interlaboratory comparison this might be an overestimate and therefore can be regarded as worst-case scenario. But if the routine samples are more complex than the interlaboratory test samples (especially with regard to inhomogeneity) than it might be an underestimate for routine analysis.

46





12


265

Slide 47 If we take the reproducibility standard deviation from a standard we have to prove that we are able to perform in accordance with the standard, i.e. that we have no reasonable bias and the repeatability of our measurement is close to that described in the standard. If this is the case, our expanded uncertainty U is twice the reproducibility standard deviation.

Reproducibility Standard Deviation from a Standard The laboratory must first prove that they are able to perform in accordance with the standard method No “unusual” bias Verification of the repeatability

The expanded uncertainty then is:

U = 2 ⋅ sR 47



Slide 48 This slide shows an example taken from an European standard for the analysis of mercury in water. For drinking water the standard states a reproducibility variation coefficient of 30% on a mercury concentration level of 0.8 µg/l. Provided that we can prove that we can perform as described in the standard our expanded measurement uncertainty (95% confidence) is estimated to 60%.

Reproducibility standard deviation from a standard Example – Mercury according to EN 1483 reproducibility variation coefficient

drinking water surface water waste water

Expanded uncertainty for drinking water: U = 2 ⋅ VCR ≈ 60 % 48



Slide 49 We also can take suitable data from a proficiency test (PT). In this case the laboratory must have participated in the PT successfully. We also have to consider, if the PT covered all relevant uncertainty components and steps of analysis. This includes e.g. if the matrix of the PT sample was similar to routine samples. If this is the case, we again calculate U from 2 · sR.

Reproducibility Standard Deviation from a PT The laboratory must have been successfully participating in the PT If the comparison covers all relevant uncertainty components and steps (matrix?) The expanded uncertainty then also is:

U = 2 ⋅ sR 49



266


Slide 50

52,25 40,07 39,06 31,65 25,40 39,10 30,78 24,65 30,25 29,16 28,46 22,29

außerhalb oben

außerhalb [%]

außerhalb unten

0,341 0,830 1,333 2,352 2,960 2,927 3,973 4,963 4,829 5,486 6,051 7,481

-41,60 37 3 1 -33,46 39 3 1 -32,75 39 1 0 -27,36 41 2 2 -22,55 38 0 1 -32,78 40 1 0 -26,71 41 1 1 -21,96 38 5 1 -26,31 39 2 0 -25,48 40 1 3 -24,94 38 5 2 -20,06 40 2 2 Summe 470 26 14

10,8 10,3 2,6 9,8 2,6 2,5 4,9 15,8 5,1 10,0 18,4 10,0 8,5

Anzahl Werte

22,86 0,889 18,09 1,748 17,67 2,756 14,60 4,263 11,90 4,793 17,69 6,057 14,23 7,090 11,57 7,928 14,00 8,536 13,54 9,508 13,24 10,357 10,53 11,444

reproducibility variation coefficient

Ausschlussgrenze unten [%]

Ausschlussgrenze oben [%]

0,1334 0,2256 0,3502 0,4726 0,4550 0,7704 0,7712 0,7361 0,9177 0,9965 1,0672 0,9854

Ausschlussgrenze unten [µg/l]

rob. Standardabweichung [µg/l]

0,584 1,248 1,982 3,238 3,822 4,355 5,421 6,360 6,553 7,361 8,063 9,359

Ausschlussgrenze oben [µg/l]

Vorgabe [µg/l]

1 2 3 4 5 6 7 8 9 10 11 12

rel. Standardabweichung [%]

Niveau

This slide shows an example from a Reproducibility Standard Deviation from a PT drinking water PT provided by the Example – Mercury in a Univ. Stuttgart PT University of Stuttgart. At the same level as in the previous example we uc = sR ≈ 20% U ≈ 40% find a reproducibility variation coefficient of about 20%. So our expanded uncertainty is estimated to 40%. Without doing anything, but looking into some papers, we therewith have two estimates of our expanded uncertainty, 60% and 40%. This shows the uncertainty of this uncertainty estimation. 50





Slide 51 We have seen two different approaches to estimate the measurement uncertainty. One was using data from control charts, CRM analysis, PT results and/or recovery tests and sometimes maybe also experience of the analyst, the other was just using the reproducibility standard deviations from interlaboratory tests. In most cases the second method delivers higher estimates.

Summary of the NORDTEST Approach Two different methods to estimate the measurement uncertainty have been introduced: Method a) Estimation of the within-lab reproducibility (mainly from control charts) Estimation of the bias (from analyses of CRM, PT results or recovery tests) Combination of both components

Method b) direct use of the reproducibility standard deviation from standards or P Ts as combined standard uncertainty

As a rule method b) delivers higher measurement uncertainties (conservative estimation) 51



Slide 52 If we report the measurement uncertainty to our customer we always have to state also the level of confidence of the range we report as uncertainty. Otherwise the uncertainty statement is completely useless. It could be helpful, also to state the method that was used to estimate the uncertainty.

Expression of Uncertainty The statement of uncertainty always has to contain the level of confidence If possible also state the estimation method used Example: SO42- in w aste water (ISO 10304-2): 100 ± 8 mg/l* * Measurement uncertainty was derived from results of interlaboratory comparisons. It represents an expanded uncertainty w ith a coverage factor k=2; this corresponds to a level of confidence of about 95%.

52



12


267

Slide 53 Once we know an estimate of the measurement uncertainty another problem comes up. How do we handle those uncertainties in compliance assessment? The ideas described here are taken from a EURACHEM/CITAC- Guide.

Uncertainties and Limits How can we handle uncertainties in the assessment of values with respect to limits From: EURACHEM/CITAC Guide “Use of uncertainty information in compliance assessment, 2007 53


Slide 54



Let us assume we have an upper limit Assessment of Compliance with an for compliance of a product and we Upper Limit have four different values, where one is together with its complete expanded uncertainty range above the limit (i) and one is completely below the limit (iv). The other two values have ranges of expanded uncertainty that include the limit. In one case the measurement result itself is above the limit (ii), in the other case below(iii). Now we have to decide, which of the four tested products are compliant and which are not. Koch, M.: Measur ement Uncertaint y


54



Slide 55 The key for that decision is a decision rule. The most important point is to decide about an acceptable level of probability of making a wrong decision and who has to take this risk. The next slides will explain how such decision rules can be developed.

Decision Rules The key to the assessment are the „decision rules“ Based on The measurement result, Its uncertainty, The specification limit

And taking into account The acceptable level of the probability of making a wrong decision

These rules give a prescription for the acceptance or rejection of a product 55



268


Slide 56 We have to formulate decision rules in such a way that we define acceptance zones (where the product is declared compliant) and rejection zones (where the product is declared noncompliant).

Acceptance Zone – Rejection Zone Based on the decision rules such zones are defined If the measurement lies in the acceptance zone the product is declared compliant If the measurement lies in the rejection zone the product is declared non-compliant

56



Slide 57 One possibility is the rule described here. With that rule we accept also such values that itself are above the limit, but not with its complete uncertainty range.

Simple Decision Rules – 1st Example „A result implies non-compliance with an upper limit if the measured value exceeds the limit by the expanded uncertainty.“ With this decision rule only case (i) in the figure would imply non-compliance

57


Slide 58 This is a rule that works the other way around. Compliance is stated only when the value and its complete uncertainty range is below the limit.



Simple Decision Rules – 2nd Example „A result implies non-compliance with an upper limit if the measured value exceeds the limit minus the expanded uncertainty.“ With this decision rule only case (iv) in the figure would imply compliance

58



12


269

Slide 59 A widely used example is not to take into account the uncertainty when deciding upon compliance. But in this case it necessary to specify a maximum allowed uncertainty. Otherwise the risk of making a wrong decision is unknown.

Simple Decision Rules – Another Widely Used „A result equal to or above the upper limit implies non-compliance and a result below the limit implies compliance, provided that the uncertainty is below a specified value.“ This is normally used where the uncert ainty is so small compared with the limit that the risk of making a wrong decision is acceptable To use such a rule without specifying the maximum permitted value of the uncertainty would mean that the probability of making a wrong decision would not be known With this decision rule, cases (i) and (ii) would imply noncomplianc e, cases (iii) and (iv) compliance 59


Slide 60 Of course it is also possible to decide that in cases where the limit is within the uncertainty range, other measures have to be taken, e.g. more measurements (to reduce the uncertainty range) or to decide to sell the product at a different price.



More Complicated Decision Rules Decision rules may include, for example, that for cases (ii) and (iii) in the figure, additional measurement(s) should be made, or That the manufactured product might be compared with an alternative specification to decide on possible sale at a different price 60


Slide 61 To define the above mentioned acceptance and rejection zones we need a specification and a decision rule.



Basic Requirements for the Decision A specification giving upper and/or lower permitted limits of the characteristics (measurands) being controlled A decision rule that describes how the measurement uncertainty will be taken into account with regard to accepting or rejecting a product according to its specification and the result of a measurement The limit(s) of the acceptance or rejection zone (i.e. the range of results), derived from the decision rule, which leads to acceptance or rejection when the measurement result is within the appropriate zone 61



270


Slide 62 If we use the decision rule from the 1st Acceptance and Rejection Zones example (slide 57) the acceptance for an Upper limit zone increases the upper limit. That a) high confidence of means that we have a high confidence correct rejection (1 example) of correct rejection. If we transform this to the sale of a commercial product, b) high confidence of the purchaser takes the risk of a wrong correct acceptance decision. (2 example) nd If we use the decision rule from the 2 example (slide 58), the seller takes the risk of a wrong decision. The decision that does not take into account the uncertainty, does not create any “guard bands”, i.e. seller and purchaser are sharing the risk. But in order to ‘know’ what risk they are sharing, they should know about a maximum uncertainty. st

nd

62





Slide 63 Of course it is possible to define decision rules also in cases where we have upper and lower limits. The example here shows a case where the risk of false acceptance is low, the seller has to take the risk of a wrong decision. A wrong decision would mean that the seller is not able to sell a product which is in fact compliant.

Acceptance and Rejection Zones for Simultaneous Upper and Lower Limits Acceptance and rejection zones for low risk of false acceptance

63



12


271

Slide 64 In some fields where measurement results are used, it is not yet common practice to explicitly define decision rules. The best way to do it, is in the product specification or the regulation. Where this is not the case, it should be clarified as part of the analytical requirement by the customer. When compliance or non-compliance is reported, it should be clear to all involved parties, which decision rules were used.

Who Defines the Decision Rule? The relevant product specification or regulation should ideally contain the decision rules Where this is not the case then they should be drawn up as part of the definition of the analytical requirement (i.e. during contract review) When reporting on compliance, the decision rules that were used should always be made clear 64



Slide 65 A lot of guidance on how to estimate measurement uncertainties is available. All guides are freely available from the internet.

Guidance Documents

ISO Guide 98: “ Guide to the expression of uncertainty in measurement” (www.bipm.org) EURA CHEM/CITA C: Quantifying Uncertainty in Analytical Measur ement, 2nd Edition (2000) (www.eurachem.org) NORDTEST: Handbook for calculation of measurement uncertainty in environmental laboratories. Report TR 537 (www.nordicinnovation.net/nordtest.cfm) LGC/VAM: Development and Har monisation of Measurement Uncertainty Pr inciples Part(d): Pr otocol for uncertainty evaluation from validation data (www.vam.org.uk) Niemelä, S.I.: Uncertainty of quantitative deter minations der ived by cultivation of microorganis ms. MIKES- Publication J4/2003 (www.mikes.fi) EA Guidelines on the Ex pression of Uncertainty in Quantitative Testing EA-4/16 (rev.00) 2003 (www.european-accreditation.org) ILAC- G17:2002 Introducing the Concept of Uncertainty of Measurement in Testing in Association w ith the Application of the Standard ISO/IEC 17025 (www.ilac.org) A2LA: Guide for the Es timation of Measurement Uncertainty In Testing, 2002 (www.a2la.net) EUROLAB: Measurement uncertainty revisited: Alternative approaches to uncertainty evaluation, 2007 (www.eurolab.org) EURA CHEM/CITA C Guide “ Use of uncertainty infor mation in compliance assessment, 2007 (www.eurachem.org) 65



Bibliography A2LA (2002) Guide for the Estimation of Measurement Uncertainty In Testing, available from www.a2la.net EA (2003) Guidelines on the Expression of Uncertainty in Quantitative Testing EA-4/16 (rev.00), available from www.european-accreditation.org EURACHEM/CITAC (2000) Quantifying Uncertainty in Analytical Measurement, 2nd Edition, available from www.eurachem.org EURACHEM/CITAC (2007) Use of uncertainty information in compliance assessment, available from www.eurachem.org EUROLAB (2007) Measurement uncertainty revisited: Alternative approaches to uncertainty evaluation, available from www.eurolab.org

272


ILAC (2002) G17 - Introducing the Concept of Uncertainty of Measurement in Testing in Association with the Application of the Standard ISO/IEC 17025, available from www.ilac.org ISO/IEC Guide 98:1995 Guide to the expression of uncertainty in measurement (GUM), also available as JCGM 100:2008 from www.bipm.org ISO/IEC Guide 99:2007 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM), 3rd edition, also available as JCGM 200:2008 from www.bipm.org ISO/TS 21748:2004 Guidance for the use of repeatability, reproducibility and trueness estimates in measurement uncertainty estimation LGC/VAM (2000) Development and Harmonisation of Measurement Uncertainty Principles Part(d): Protocol for uncertainty evaluation from validation data, available from www.vam.org.uk Niemelä SI (2003) Uncertainty of quantitative determinations derived by cultivation of microorganisms. MIKES-Publication J4/2003, available from www.mikes.fi NORDTEST (2004) Handbook for calculation of measurement uncertainty in environmental laboratories. Report TR 537 available from www.nordicinnovation.net/ nordtest.cfm

13

Control Charts

Michael Koch and Michael Gluschke Control Charts may be the most powerful tool to demonstrate and to assure quality in chemical measurements. Therefore they are widely used in all kinds of laboratories and it is hard to imagine quality management systems in laboratories without control charts. Slide 1 ISO/IEC 17025 requires quality control procedures and, where practicable, the use of statistical techniques to monitor the validity of tests and detect possible trends.

Assuring the Quality of Test and Calibration Results - ISO/IEC 17025 – 5.9 The laboratory shall have quality control procedures for monitoring the validity of tests and calibrations undertaken. The resulting data shall be recorded in such a way that trends are detectable and, where practicable, statistical techniques shall be applied to the reviewing of the results. 1

Koch, M., Glu sch ke, M.: Control Charts In: W enclawiak, Koch, Hadj icostas (eds.)


Slide 2 These actions have to be planned and reviewed. ISO/IEC 17025 gives examples of such procedures: the use of reference materials (see chapter 14) participation in proficiency testing schemes (see chapter 15) replicate tests retesting of retained items

Assuring the Quality of Test and Calibration Results - ISO/IEC 17025 – 5.9 This monitoring shall be planned and reviewed and may include, but not be limited to, the following: regular use of certified reference materials and/or internal quality control using secondary reference materials; participation in interlaboratory comparison or proficiency-testing programmes; replicate tests or calibrations using the same or different methods; retesting or recalibration of retained items; correlation of results for different characteristics of an item. 2




273

274


Slide 3 Control charts are a very powerful technique that can be used for the control of routine analyses. ISO/IEC 17025 requires the use of such statistical techniques wherever practicable.

Control Charts Powerful, easy-to-use technique for the control of routine analyses ISO/IEC 17025 demands use wherever practicable

3

Koch, M., Glu sch ke, M.: Control Charts




Slide 4 Shewhart firstly introduced control charts in 1931 for the control of manufacturing processes. Sudden occurring changes as well as gradual worsening of quality can easily be detected. Immediate interventions reduce the risk of producing rejects and minimize client complaints.

History Introduced by Shewhart in 1931 Originally for industrial manufacturing processes For suddenly occurring changes and for slow but constant worsening of the quality Immediate interventions reduce the risk of production of rejects and complaints from the clients 4





Slide 5 The principle of control charts is very simple: Take samples during the process, measure a quality indicator and mark the result on a chart with limits.

Principle Take samples during the process Measure a quality indicator Mark the measurement in a chart with warning and action limits concentration upper action limit upper warning limit

target value

lower warning limits lower action limits

sample-#

1

2

3

4

5

6

7

8

9

10

1112

13

14

15

16

17

18

5



13

Control Charts

275

Slide 6 If control charts are transferred to Control Charts in Analytical analytical chemistry the first thing to Chemistry do is to assign the target value. If a Target value reference material / certified reference Certified value of a RM/CRM material (RM/CRM) is used, the Mean of often repeated measurements of certified value can be used as the the control sample target value. This is advisable only, if the mean of the measurements is close to the reference value. Otherwise out-of-control situations would occur very frequently. So in most cases the arithmetic mean of the measurements is used as target value. Koch, M., Glu sch ke, M.: Control Charts


6



Slide 7 For the warning and action limits there is a convention to use the ± 2s- and ± 3s-range respectively. If the data are normally distributed, 95.5% of the data are within μ ± 2σ and 99.7% within μ ± 3 σ. Since µ and σ are always unknown in analytical chemistry, the estimated values x and s are used.

Control Charts in Analytical Chemistry Warning / action limits If data are normal distributed 95.5% of the data are in µ ± 2σ 99.7% are in µ ± 3σ

x ± 2s is taken as warning limits x ± 3s is taken as action limit 7



Slide 8 The probability that 99.7 % of the “correct” measurement results are Action Limits expected to lie within the action limits There is a probability of only 0.3 % that means that only 3 out of 1000 correct a (correct) measurement is outside the measurement results will lie outside action limits (3 out of 1000 this range. “Correct” means that they measurements) Therefore the process should be belong to the same statistical distribustopped immediately and searched for tion of data. Therefore the probability errors is very high that a result that is outside the action range is incorrect. If such a value is obtained the process should be stopped immediately and examined for errors. Koch, M., Glu sch ke, M.: Control Charts




8

276


Slide 9 The probability of correct data to be outside the warning limits is 4.5%. This is a reasonably high probability. Therefore such values should only give a warning signal and no immediate action is required.

Warning Limits 4.5% of the (correct) values are outside the warning limits. This is not very unlikely. Therefore this is only for warning, no immediate action required.

9



Slide 10 There are different standard deviations Calculation of Standard depending on the measurements Deviation conditions: repeatability conditions, Measurements marked in the control between-batch and interlaboratory chart are between-batch reproducibility conditions. Standard deviation should also be between-batch The measurements on the control Estimation from a pre-period of about sample usually are made with each 20 working days batch and finally marked on the Repeatability STD Î too narrow limits control chart are done under between Interlaboratory STD Î too wide limits batch conditions. Therefore the standard deviation for the calculation of the limits should also be determined under the same between-batch conditions. The most common way to estimate this standard deviation is to use the results from a pre-period of about 20 working days. The use of the repeatability standard deviation would result in too narrow limits whilst interlaboratory conditions would lead to limits that are too wide.

10





Slide 11 Limits Ù Fitness for Purpose

Warning and action limits calculated in the above way should not be used without considering the “fit for the purpose” requirement. The limits may be too narrow or too wide for the analytical purpose. If this is the case the limits should be adjusted to such requirements.

Action and warning limits have to be compatible with the fitness-for-purpose demands No blind use

11



13

Control Charts

277

Slide 12 The following slides will show some situations that are very unlikely to occur with normally distributed data and therefore should be treated as out-of-control situations. This slide shows a value that is outside the action limit.

Out-of-control Situation 1 Suddenly deviating value, outside the action limits concentration upper action limit upper warning limit

target v alue

lower warning limit

12

13

14

date

.06 .20 06 .06 .200 6 .06 .20 15 .06 06 .20 06 16 .06 .20 06 19 .06 .200 20 6 .06 .20 06 21 .06 .20 0 22 .06 6 .200 23 .06. 6 200 26 6 .06. 200 27 .06 6 .200 6

lower action limit

12

Slide 13 Although it is not very unlikely that a single value is outside the range defined by the warning limits, the probability that two out of three successive values are outside this range is very low. Hence this should be treated as an out-of-control situation as well.



Out-of-control Situation 2 2 of 3 successive values outside the warning limits concentration upper action limit upper warning limit

target v alue

lower warning limit

12

13

14

date

.06 .20 06 .06 .200 6 .06 .20 15 .06 06 .20 06 16 .06 .20 06 19 .06 .200 20 6 .06 .20 06 21 .06 .20 0 22 .06 6 .200 23 .06. 6 200 26 6 .06. 200 27 .06 6 .200 6

lower action limit

13



Slide 14 In analytical chemistry there are many possibilities that can lead to a systemOut-of-control Situation 3 7 successive values on one side of the atic shift in the measurement results. If central line seven successive values are on one side of the central line the process should also be stopped and the reason should be investigated. Please not that in this case the fitness-for-purpose criteria are still fulfilled since of all of the data are within the warning limits. So the situation is not as critical as in the previous situations. Nevertheless the data show that something happened to our dataset and we should investigate that. concentration

upper action limit

upper warning limit

target v alue

lower warning limit

12

13

14

date

.06 .20 06 .06 .200 6 .06 .20 15 .06 06 .20 06 16 .06 .20 06 19 .06 .200 20 6 .06 .20 06 21 .06 .20 0 22 .06 6 .200 23 .06. 6 200 26 6 .06. 200 27 .06 6 .200 6

lower action limit



14



278


Slide 15

Out-of-control Situation 4 7 successive increasing or decreasing values concentration upper action limit upper warning limit

target v alue

lower warning limit

12

13

date

.06 .20 06 .06 .200 6 .06 .20 15 .06 06 .20 06 16 .06 .20 06 19 .06 .200 20 6 .06 .20 06 21 .06 .20 0 22 .06 6 .200 23 .06. 6 200 26 6 .06. 200 27 .06 6 .200 6

lower action limit

14

Slow but constant changes of the equipment or of chemicals will lead to a trend in the control chart. After seven increasing or decreasing values the reason should be investigated. Here the same applies as in the previous situation as long as the warning limits are not exceeded repeatedly.

15


Slide 16 Although it is possible to handle the data of the control analyses in a table it is much faster, much more illustrative and much clearer to have a graphical display of the data.



Advantages of Graphical Display Much faster More illustrative Clearer 16



Slide 17 In the following slides different Different Control Charts control charts are shown. The first and X-chart most frequently used is the X-chart. Synonyms are X-control chart, mean control Synonyms are X-control chart, mean chart or average control chart Original Shewhart-chart with single values control chart or average control chart. Mainly for precision check This chart corresponds to the original For trueness control synthetic samples with known content or RM/CRM samples may be Shewhart-chart. For trueness control, analysed standard solutions, synthetic samples It is also possible to use calibration parameters (slope, intercept) to check the plausibility of the or RM/CRM samples may be calibration analysed. Calibration parameters (slope and intercept) can also be used in a X-chart to check the constancy of the calibration. Koch, M., Glu sch ke, M.: Control Charts


17



13

Control Charts

279

Slide 18 The Blank Value Chart is also very important. This is a special form of a Shewhart chart where the direct measurements (e.g. in Volts) from the analyses of blank samples are used. From this chart information can be received about contamination of reagents e.g. from the environment and the state of the analytical system.

Different Control Charts Blank Value Chart Analysis of a sample, which can be assumed to not contain the analyte Special form of the X-chart Information about The reagents The state of the analytical system Contamination from environment

Enter direct measurements, not calculated values 18



Slide 19 The Recovery Rate Chart reflects the influence of the sample matrix. Values from the analysis of a spiked and nonspiked sample are used.

Different Control Charts Recovery Rate Chart - I Reflects influence of the sample matrix Principle: Analyse actual sample Spike this sample with a known amount of analyte Analyse again

Recovery rate:

⎞ ⎛x −x RR = ⎜ spiked unspiked ⎟ ⋅ 100 % ⎜ Δx expected ⎟⎠ ⎝




Slide 20 Proportional systematic errors are Different Control Charts detected with a Recovery Rate Chart, Recovery Rate Chart - II but not constant systematic errors (e.g. Detects only proportional systematic too high blank values). Additionally errors the spiked analyte might be bound to Constant systematic errors remain undetected the matrix differently. This possibly Spiked analyte might be bound results in a higher recovery rate for the differently to the sample matrix Î better spike than for the originally bound recovery rate for the spike Target value: around 100% analyte. The mean value (usually used as the target value) should be around 100%. If the mean deviates the laboratory has to decide on the background f the fitnessfor-purpose if this deviation is acceptable. Koch, M., Glu sch ke, M.: Control Charts


20



280


Slide 21 Often analyses are carried out more Different Control Charts than once. In this case the range Range Chart between the repeated measurements Synonyms are R-chart or Precision chart. Absolute difference between the highest and can also be used in a control chart. lowest value of multiple analyses This is the Range Chart. It can be used Precision check only as a repeatability precision check, Control chart has only upper limits because the target value for the analysis is not known. This chart only has upper limits. It can be used with the range itself (R-chart) or with the percentage difference (R%-chart). The latter is used if the percentage range is expected to be more constant in the respective concentration range than the range itself. concentration

upper action limit

upper warning limit

target value

sample-#

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15



16

17

18

21



Slide 22 The Difference Chart is very similar to the range chart but it uses the difference between double measurements together with its sign. The sample is measured at the beginning and at the end of a series. The difference between the two measurements is marked in the control chart with its sign.

Different Control Charts Difference Chart - I Uses difference with its sign Analyse actual sample at the beginning of a series Analyse same sample at the end of the series

Calculate difference (2nd value – 1st value) Mark in control chart with the sign

22



Slide 23 The target value of a Difference Chart should be around zero. Otherwise there is a drift in the analyses during the series and again the laboratory has to decide if this is acceptable. If not, the calibration of the method has to be made more frequently. A Difference Chart gives information about precision and drift.

Different Control Charts Difference Chart - II Target value: around 0 Otherwise: drift in the analyses during the series

Appropriate for precision and drift check

23



13

Control Charts

281

Slide 24 The Cusum Control Chart is a very special chart from which a lot of information can be drawn. Cusum is the abbreviation for cumulative sum and means the sum of all differences from the target value. Every day the difference of the control analysis from the target value is added to the sum of all the previous differences.

Different Control Charts Cusum Chart - I Highly sophisticated control chart Cusum = cumulative sum = sum of all differences from one target value Target value is subtracted from every control analyses and difference added to the sum of all previous differences 24





Slide 25 This slide gives an example of the use of a Cusum Chart. The upper chart is a conventional X-chart, the lower one a Cusum Chart. Starting from the 11th value, all values are below the target value originating from slow betweenbatch-drift in the analyses. This can be seen in the Cusum Chart by a descending cumulative sum.

Different Control Charts - Cusum Chart - II T = 80 Nr. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

s = 2.5 x x-T Cusum 82 +2 +2 79 -1 +1 80 0 +1 78 -2 -1 82 +2 +1 79 -1 0 80 0 0 79 -1 -1 78 -2 -3 80 0 -3 76 -4 -7 77 -3 -10 76 -4 -14 76 -4 -18 75 -5 -23

90

85

80

75

70 0

2

4

6

8

10

12

14

16

4

6

8

10

12

14

16

30 20 10 0 0

2

-10 -20 -30

25





Slide 26 For the evaluation of a Cusum Chart a V-mask is used. This mask is laid on the chart so that the last marked value has a distance of d from the peak. With the correct choice of the distance d and the angle Θ, the relation between false positive and false negative alarms can be adjusted for an individual optimum.

Different Control Charts - Cusum Chart - III V-mask as indicator for out-of-control situation 30

30

in control

20

10

0

0 0

2

4

6

8

10

12

14

out of control

20

10

16

0

-10

-10

-20

-20

-30

-30

2

4

6

8

10

12

14

16

Choose d and Θ so that Θ d

Very few false alarms occur when the process is under control but An important change in the process mean is quickly detected


26


282


Slide 27 The Cusum Chart shows very clearly the point from which the process ran out of control. The average run length, i.e. the time needed to detect an outof-control situation is shorter than for other control charts. Furthermore, the size of a change in the process can be detected from the slope of the chart.

Different Control Charts Cusum Chart - IV Advantages It indicates at what point the process went out of control The average run length is shorter Number of points that have to be plotted before a change in the process mean is detected

The size of a change in the process mean can be estimated from the average slope 27



Slide 28 Target control charts are control charts with fixed quality criterions. In the contrary to classical control charts of the Shewhart-type these control charts operate without statistically evaluated values. The limits for this type of control charts are given by external prescribed and independent quality criterions.

Different Control Charts Target Control Charts - I In the contrary to classical control charts of the Shewhart-type the target control charts operates with fixed quality criterions and without statistically evaluated values The limits for this type of control charts are given by external prescribed and independent quality criterions (fitness for purpose)

28



Slide 29 We can convert all types of classical control chart (X-chart, blank value, recovery, range control chart etc.) into target control charts. Situations for which a target control chart is appropriate are described in this slide.

Different Control Charts Target Control Charts - II All types of classical control chart (X-chart, blank value, recovery, R-, R%-chart etc.) can be used as a target control chart A target control chart is appropriate if: There is no normal distribution of the values from the control sample due to persisting out of control situations (e.g. blank values) There are not enough data available for the statistical calculation of the limits (rarely analysed parameters) There are external prescribed limits which have to be applied to ensure the quality of analytical values 29



13

Control Charts

283

Slide 30 The control samples for the target control charts and their measures are the same as for the classical control charts. The limits are given by different external quality criterion, described in the slide.

Different Control Charts Target Control Charts - III The control samples for the target control charts are the same as for the classical control charts The limits might be given by Requirements from legislation Standards of analytical methods and requirements for internal quality control The (minimum) laboratory-specific precision and trueness of the analytical value, which have to be ensured The evaluation of laboratory-intern known data of the same sample type 30





Slide 31 The chart is constructed with an upper and lower limit. A pre-period is not necessary. The target control chart of the range and in some cases also of the blank only needs the upper limit. The analytical method is out-ofcontrol, if the analytical value is higher or lower than the respective prescribed limits. Nevertheless trends in the analytical quality should be identified and steps should be taken against them.

Different Control Charts Target Control Charts - IV Constructed with an upper and lower limit Pre-period is not necessary Out-of-control only, if the analytical value is higher or lower than the respective limit Nevertheless trends in the analytical quality should be identified and steps should be taken against them 31





Slide 32 Different Control Charts Target Control Charts - V (example) only two limits and one out-of-cont rol situation Control period

Ammonia RM (µmol/l)

17

Values

mean

upper CL

upper WL

lower WL

lower CL

mean+1s

mean-1s

16 15 14 13 12 11 10

18.07.2003

16.07.2003

15.07.2003

15.07.2003

11.07.2003

10.07.2003

09.07.2003

08.07.2003

02.07.2003

26.06.2003

25.06.2003

24.06.2003

19.06.2003

18.06.2003

17.06.2003

16.06.2003

13.06.2003

13.06.2003

11.06.2003

27.05.2003

22.05.2003

21.05.2003

8

20.05.2003

9 16.05.2003

This slide shows a target control chart for ammonia reference material measurements. The chart was constructed with the Excel® tool ExcelKontrol 2.1, which also is included in the electronic material to this book. In contrary to the classical control chart here only two limits and one out-of-control situation (outside control limits) are usually used.

Comment / Out-of-control situation / Action

Date

Value

16.05.2003

12,61

Check

12,96

Check

DB 1,2,6

12,36

Check

DB 10, 16, 19

20.05.2003 21.05.2003

WB/O v. 14.5./KB v. 15.5.

22.05.2003

12,66

Check

SH v. 21.5.03

27.05.2003

12,58

Check

RB

11.06.2003 13.06.2003

11,45

Check

UW/O/KB v. 10.6

12,28

Check

UW/O/KB Wdh.

13.06.2003

12,28

Check

O / SH v. 11.6.

16.06.2003

12,05

Check

WB v. 12.6.03

12,93

Check

RB/DB

13,13

Check

O/KB

19.06.2003

12,79

Check

DB

24.06.2003

12,47

Check

GB/S/P

25.06.2003

12,07

Check

OB/O/GB

26.06.2003

12,6

Check

RB

17.06.2003 18.06.2003

02.07.2003

12,37

Check

08.07.2003

13,06

Check

09.07.2003

13,29

Check

O/UW/KB v. 1.7.03 O/KB/RB QCl neu OB/O/GB KH P 9.7. / SH 3.7.03

10.07.2003

13,75

Check

11.07.2003

13,88

Check

15.07.2003

15,62

Check

15.07.2003

14,3

Check

DB Wdhl QCl neu

16.07.2003

13,01

Check

O v. 2.7.

18.07.2003

14,09

Check

WB v. 2.7.03

GB/S/P Out of Control A DB

Check Check Check

32



284


Slide 33 This slide contains links to EXCELsheets from ExcelKontrol 2.1. This sheets can be used to run control charts with checks for out-of-control situations and with graphical displays. In the electronic material you will find the whole zipped program, which also allows target control charts. Details and updates you will find in the internet (http://www.labcontrolexcel.org).

EXCEL-Tool for Control Charts ExcelKontrol 2.1 X-/mean-charts Blank value chart

Range chart with absolute ranges Range chart with relative ranges Recovery rate chart Differences chart 33



Slide 34 Control samples are a prerequisite for every control chart. They have to fulfil certain requirements that are shown in this slide.

Control Samples No control chart without control samples Requirements: Must be suitable for monitoring over a longer time period Should be representative for matrix and analyte conc. Concentration should be in the region of analytically important values (limits!), if possible Amount must be sufficient for a longer time period Must be stable for several months No losses due to the container No changes due to taking subsamples 34


Slide 35 There are various possibilities for control samples. Their advantages and disadvantages are shown in the next slides. Provided that standard solutions are completely independent from the calibration solutions they can be used to verify the calibration. But the influence of a sample matrix cannot be detected. Therefore only a limited precision check and only a very little control of trueness are possible.



Control Samples Standard Solutions To verify the calibration Control sample must be completely independent from calibration solutions Influence of sample matrix cannot be detected Limited control for precision Very limited control for trueness 35



13

Control Charts

285

Slide 36 Blank samples, i.e. samples that can be assumed to not contain the analyte, are necessary for blank value charts. With such samples it is possible to detect the errors listed in the slide.

Control Samples Blank Samples Samples which probably do not contain the analyte To detect errors due to

Changes in reagents New batches of reagents Carryover errors Drift of apparatus parameters

Blank value at the start and at the end allow identification of some systematic trends 36



Slide 37 Real samples can be used for Range and Difference Charts. They deliver a rapid repeatability precision control, but no trueness check. If different matrices are analysed it might be useful to separate the results from different matrices in different charts.

Control Samples Real Samples Multiple analyses for range and differences charts If necessary separate charts for different matrices Rapid precision control No trueness check 37



Slide 38 Real samples that are analysed with and without a spike are used for the Recovery Rate Chart. It is necessary to consider, whether the sample used for control has a representative matrix and whether the spike is bound to the matrix in the same way as the analytes in the sample.

Control Samples Real Samples Spiked with Analyte For recovery rate control chart Detection of matrix influence If necessary separate charts for different matrices Substance for spiking must be representative for the analyte in the sample (binding form!) Limited check for trueness 38



286


Slide 39 Synthetically mixed samples are in very rare cases representative for real samples. Nevertheless, if they are, they can provide good checks on precision and trueness.

Control Samples Synthetic Samples Synthetically mixed samples In very rare cases representative for real samples If this is possible Î precision and trueness check

39



Slide 40 CRMs would be the ideal control samples, but they normally are too expensive and very often not available. In-house reference materials that are regularly checked against a CRM under repeatability conditions are a good alternative. If retained sample material from an interlaboratory test is available and it is stable after the test is finished, this also can be used as an in-house reference material.

Control Samples Reference Materials CRM are ideal control samples, but Often too expensive or Not available

In-house reference materials are a good alternative Can be checked regularly against a CRM If the value is well known Î good possibility for trueness check

Sample material from interlaboratory tests 40



Slide 41 There are many possible control charts for each analysis. This leads to the Which One? questions, which is appropriate and There are a lot of possibilities how many control charts are necessary. Which one is appropriate? There is no general answer to these How many are necessary? questions except that the quality control measures have to be fit for the The laboratory manager has to decide! purpose of the analyses. But there can be assistance The laboratory manager has to decide, what he thinks is “fit for the purpose” (and the assessor in the accreditation process will assess this decision). But there are some general rules: Koch, M., Glu sch ke, M.: Control Charts


41



13

Control Charts

287

Slide 42 For frequently used methods control charts are absolutely necessary. If all the samples that are analysed have the same matrix, the sample preparation should be included in the control procedure. If the matrix changes very often, it could be useful to limit the procedure to the measurement step only.

Choice of Control Charts - I The more frequent a specific analysis is done the more sense a control chart makes If the analyses are always done with the same sample matrix, the sample preparation should be included. If the sample matrix varies, the control chart can be limited to the measurement only 42



Slide 43 Some standards or decrees include the obligatory measurement of control samples or repeated measurement. This can be used for control charts with only little effort. Other values like calibration parameters are also available without additional work. They also can be used for control charts, especially if the stability of calibration is known to be a weak point in the procedure.

Choice of Control Charts - II Some standards or decrees include obligatory measurement of control samples or multiple measurements. Then it is only a minimal additional effort to document these measurements in control charts In some cases the daily calibration gives values (slope and/or intercept) that can be integrated into a control chart with little effort 43



Slide 44 Control charts are a very powerful tool for quality control and should be used as a matter of course in every laboratory.

Benefits of Using Control Charts A very powerful tool for internal quality control Changes in the quality of analyses can be detected very rapidly Good possibility to demonstrate ones quality and proficiency to clients and auditors 44



288


Bibliography: Duncan AJ (1965) Quality Control and Industrial Statistics, R.D. Irwin Inc., Homewood, Illinois Farrant TJ (1997) Practical Statistics for the Analytical Scientist – a Bench Guide. Royal Society of Chemistry for the Laboratory of the Government Chemist (LGC), Teddington Funk W, Dammann V, Donnevert, G (2006) Quality Assurance in Analytical Chemistry. 2nd edition, Verlag Wiley VCH Weinheim ISO 8258:1991 – Shewhart control charts Miller JC, Miller JN (2005) Statistics and Chemometrics for Analytical Chemistry. 5th edition, Pearson Education, Harlow Montgomery DC(1985) Introduction to Statistical Quality Control, Wiley New York NORDTEST: Internal Quality Control – Handbook for Chemical Laboratories. NORDTEST Report TR 569, available from www.nordicinnovation.net/ nordtest.cfm. Shewhart W (1931) The Economic Control of Quality of Manufactured Product. D. van Nostrand Company, New York Wernimont G (1946) Use of Control Charts in the Analytical Laboratory. Industrial and Engineering Chemistry, Analytical Edition 18, 587-592

14

(Certified) Reference Materials

Ioannis Papadakis This chapter gives an overview of the role of reference materials in quality assurance in analytical laboratories. Slide 1 Index

The presentation gives some definitions that are important to the selection use Definitions - documentation and production of reference materials Types of (C)RMs Production of (C)RMs and provides documentation for Selection and use of (C)RMs further reading and study. There is CRMs and traceability discussion on the different types of Suppliers/producers of (C)RMs reference materials with some insight into their production process. This is followed by information relevant to selection and use of reference materials with a discussion on the relation between reference materials and traceability, which is very important in the context of this presentation. Finally some internet addresses are given of the major certified reference materials producers. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

1



Slide 2 ISO Guides

Over the last years a lot of work has been done in the reference materials ISO 30 (1992) terms and definitions used in connection with RMs area by the International Organization ISO 31 (2000) certificates of RMs of Standardization (ISO). ISO 32 (1997) calibration in analytical chemistry and use of CRMs A special committee (ISO-REMCO) ISO 33 (2000) uses of CRMs prepared many guidance documents ISO 34 (2009) general requirements for the competence of RM producers relevant to reference materials. ISO 35 (2006) certification of RMs A list of these ‘guides’ is given here. This list is quite exhaustive starting from ‘terms and definitions’ and going into details such as ‘certification’. These documents are very useful, covering most aspects of reference materials. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

2




289

290


Slide 3 Let’s see now the ISO definition of a reference material. The definition is concerned with sufficiently homogeneous and well-established property values. These values can be used for calibration of an apparatus, assessment of a measurement method or for assigning values to other materials.

Reference Material Definition Material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials 3

Papadakis, I .: (Certified) Referen ce Mater ial s

Slide 4



There also is a note in the definition, which states the obvious and says that Reference Material (RM) a reference material can be in all three A reference material may be in the form possible forms, i.e. gas, liquid or solid. of a pure or mixed gas, liquid or solid However the second part of the note is Examples are water for the calibration very interesting, because it gives some of viscometers, sapphire as a heatcapacity calibrant in calorimetry, and examples. Water can be considered as a solutions used for calibration in reference material for the calibration of chemical analysis a viscometer since for a given temperature its viscosity is homogeneous and well established. In an analogous way sapphire can be used as heat-capacity calibrant in calorimetry and in analytical chemistry various solutions are used for calibration of analytical instruments. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

4



Slide 5 Certified Reference Material Definition But what about the certified reference materials? This is a group of reference Reference material, accompanied by a certificate, one or more of whose property materials with a weighty name and values are certified by a procedure which establishes traceability to an accurate there is a lot of discussion about them. realisation of the unit in which the The ISO definition is given here. In property values are expressed, and for which each certified value is accompanied general they are reference materials, by an uncertainty at a stated level of thus they also have property values confidence sufficiently homogeneous and well established. However this is not enough. There should also be a certificate and the property values should be certified by a procedure that establishes traceability to an accurate realisation of the unit in which the property value is expressed. Moreover the certified property value should be accompanied by an uncertainty at a stated level of confidence. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)



5

14


291

Slide 6 This definition is also accompanied by notes. The first says that certified Certified Reference Material reference materials are a sub-class of (CRM) ‘measurement standards’ (or ‘etalons’). All CRMs lie within the definition of The second gives us some information “measurement standards” or “etalons” related to the usual production process CRMs are generally prepared in batches for which the property values of certified reference materials. are determined within stated uncertainty Usually certified reference materials limits by measurements on samples representative of the whole batch are prepared in batches and the property values (including the uncertainty) are determined in representative samples. To give an example, if a producer prepares 4000 vials from a batch of human serum, to be used as certified reference material for cholesterol measurements, it is neither practical nor realistic to measure the cholesterol content in all the 4000 vials. The measurements will be performed only on a number of vials. This will be discussed in more detail below. 6

Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)



Slide 7 Concerning the classification of reference materials, this usually is a matter of grouping. There is no hidden rule and it is usually done for presentation reasons. This slide presents several ways of classification, which are given in a book by Zschunke.

Classification of RMs Physical character Gases, liquids or solids

Supplied property Pure chemic al species, physico-chemical property

Preparation method Synthetic mixtures, natural materials

Metrological qualification Primary RM, secondary RM

Intended use Calibration of instruments, validation of analytical methods Reference Materials in Analy tical Chemistry - A Guide for Selection and Use, edited by A Zschunke, Springer, 2000 7



292


Slide 8 Passing from the theoretical part of the CRM Production presentation to the more practical one, According to ISO-35 the production of certified reference Producing a CRM is: materials will now be discussed. The integrated process of correct Certified reference materials are intenpreparation, homogeneity and stability demonstration, and accurate and traceable tionally chosen because they are the characterisation, Whereby all components of uncertainty of most important for quality assurance. “the sample on the desk of the user” According to the ISO guide 35, the should be properly accounted for according to the ISO-GUM (Guide to the expression of production of a certified reference uncertainty in measurement) material is an integrated process of correct preparation, demonstration of homogeneity and stability of the properties as well as accurate and traceable characterization of these properties. In addition all the components of uncertainty of “the sample on the desk of the user” should be accounted for. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

8



Slide 9 This does not sound to be very CRM Production complicated, but it certainly is not a Non-trivial Job! trivial job. It requires special skills and It requires ... sophisticated installations in order to Skills and installation to process the process materials in a suitable form, material in a suitable form, especially for matrix CRMs especially matrix certified reference (e.g. making 2000 containers of orange juice sample for heavy metals content meas urement, with demonstrated materials. Imagine a few thousand homogeneity and stability) bottles of freeze-dried orange juice Demonstrated measurement capability, to produce reference value with demonstrated homogeneity and stability for metals content! In addition there is a need for demonstrated measurement capability to produce the reference value, in other words to being able to adequately demonstrate the measurement traceability and measurement uncertainty. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)



9

14


293

Slide 10 The list presented here divides the production process into different steps. This is not the only way of dividing the production process and it does not mean that all the steps need to be followed in every case. This is a detailed description according to the perception of the author.

CRM Production Production Process

Select the material Prepare the units (e.g. bottles) Labelling Measure homogeneity Measure stability Assignment of reference values Distribution/marketing 10


Slide 11 At the beginning of the production process a decision needs to be taken concerning the proposed certified reference material. There should be a specific need in the analytical community in terms of measurement, which needs to be met and of course there should be material available in a suitable form, before taking the decision to start the process.



Select the Material Depends on the needs of the analytical community Measurement that needs to be supported Depends on availability of material

11



Slide 12 Prepare the Units The starting material (batch) after appropriate homogenization should be Select appropriate container (size, shape, material, properties …) stored in appropriate containers. Later Prepare the units (e.g. vials) under the these containers would be distributed appropriate conditions to the interested scientists in order to Each unit should contain the support their measurements. Of course, appropriate amount of material first, the appropriate containers, in Prepare appropriate number of units terms of size (large, small), shape (bottle, vial), properties (hard, soft, coloured), material (glass, plastic) have to be selected. Some other important items at this stage are the preparation of the units under the appropriate conditions (e.g. freeze-dried material under low humidity), each unit should contain an appropriate amount of material (depending on the amount needed for each measurement and the availability of the material) and the appropriate number of units has to be decided (taking into account the needs for this specific certified reference material). 12




294


Slide 13 One of the important steps in the production process is the measurement Measure Homogeneity of the homogeneity. This step ensures that all the units of the certified refer Fast measurement method ence material carry the same (within Small sample quantity the uncertainties) property value. Good reproducibility Usually for this purpose a rapid Within containers measurement method is used, which Between containers requires only a small sample quantity and gives good reproducibility. The reasons for the above is that a lot of measurements need to be performed (rapid method), the total sample quantity is given (small quantity) and there is no need for very accurate measurements since the certification measurements are performed at a later stage (but reproducibility has to be good). It must be mentioned that two ‘kinds’ of homogeneity are usually measured, one within each container and one between different containers.

13




Slide 14 Another step of the production process, equally important to the homogeneity Measure Stability measurement, is the stability measure Fast measurement method ment. The measurement method Small sample quantity requirements are the same as those for Good reproducibility the measurement of homogeneity for Different storing temperatures the same reasons. At this stage there Different times are two additional requirements. The measurements are performed on samples stored at different temperatures, in order to determine the appropriate storage temperature and at different times, in order to determine the lifetime of the certified reference material.

14




14


295

Slide 15 Probably the most important step in the production process of a certified reference material is the assignment of the reference value(s). This, in the case of a reference material, is done by designation but in the case of a certified reference material by measurement. Even when using synthetic preparation, measurements are still needed for confirmation of the preparation process.

Assignment of Reference Value

By measurement (CRM) By designation (RM)

15



Slide 16 Focusing on the assignment of the reference value by measurement, there are several ways to achieve this. It can be done either by using one measurement method (usually this should be a primary method in order to be able to demonstrate measurement traceability and measurement uncertainty), or use of one method by several laboratories or several methods by one or several laboratories.

Assignment of Reference Value by Measurement One method in one lab (e.g. a primary method) One method in several labs Several methods in several labs

16



Slide 17 The traceability of the reference value needs to be stated, but more importantly also demonstrated. In addition all the relevant information should be available in the certification report of the certified reference material.

Traceability of the Assigned Value

Needs to be stated … and demonstrated Information available in certification report

17



296


Slide 18 The uncertainty of the assigned value, Uncertainty of the Assigned as stated before, is also very important. Value (UCRM) Uncertainty of the assigned value is U uncertainty of the average concentration of the uncertainty of the average concen1 unit (of the n prepared) after storage for time T and after transport tration of 1 unit (of the n prepared) UCRM [%]=k*(u2assign+u2bb+u2lts+u2sts)1/2 after storage for time T and after transport, i.e. when the certified referu uncertainty value assignment measurement u uncertainty bottle to bottle variation ence material arrives at the desk of the uncertainty long term stability u u uncertainty short term stability (transport) user. In general this can be obtained by combining the uncertainties of the value assignment measurement, the uncertainty of the bottle to bottle variation (homogeneity), the uncertainty of the long-term stability (lifetime) and the uncertainty of the short-term stability (transport). CRM

assign bb lts

sts


18



Slide 19 Continuing with the production steps, labelling of the certified reference material is important in order to avoid confusion. Very often this step is not taken seriously with unfortunate results. It is important to have clear and concise labelling.

Labelling

Equally important Clear and concise

19



Slide 20 The final step of the production is the marketing of the certified reference material and the distribution. The most important item at this stage is the delivery of the certified reference material together with a detailed certification report with all the information relevant to the production of the material as well as advice for the intended use. The producer should also ensure that the certified reference material is

Distribution / Marketing Certification report Appropriate price Appropriate delivery Appropriate storage Reach scientific community 20



14


297

available at an appropriate price, that the delivery is done in an appropriate way and at an appropriate time. Also the certified reference material should be stored under appropriate conditions, at all times until it arrives at the customer. Finally it must be ensured that the broad scientific community is aware of its availability. Slide 21 Summarizing the production and in order to help the selection of high quality certified reference materials, in general the traceability of the certified property should be stated, the uncertainty according to ISO guidelines should be stated, both of the above should also be demonstrated and it is preferred that the certified reference material is produced according to ISO guide 35.

In General High Quality CRMs Should… State traceability of certified value

(e.g. traceability to SI, or to values obtained with method XY Z)

State an ISO-GUM uncertainty of certified value Demonstrate traceability & uncertainty of certified value (e.g. in a certification report; experimental evidence of demonstrated capability from participation to international comparis ons)

Preferably be produced according to the guidelines of ISO-35 21



Slide 22 As far as the use of the certified reference material is concerned, in an ideal Use of CRMs situation the supplier or producer (Ideally) supplier should give advice should give advice on the appropriate Storage temperature use to the user. In addition it is Influence of moisture on long term essential to obtain information relevant stability (e.g. biological activity) to storage temperature, influence of Influence of contamination moisture and influence of contamina Possibility to divide in different portions after opening tion. The possibility of dividing the certified reference material into different portions after opening in order to maintain its original properties should always be considered. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

22



298


Slide 23 Which are the main ways that a certified reference material can contribute towards better measurements? The usual answers to this question are three: Calibration, Validation and Measurement Control. Let’s investigate these three one by one.

Use of CRMs How can CRMs help my measurements? Calibration (?) Validation (?) Measurement control (?)

23



Slide 24 Calibration response

Starting with the calibration, the certified reference material can be used as a calibrant (directly or via working standards prepared using them) and in this way traceability of the results to the property values of the certified reference material is ensured. Thus this is a very ‘valid’ way for certified reference materials to improve the measurements in a laboratory.

concentration

Use as a matrix matched calibrant (direct or via working standards) to ensure traceability of results to an external reference (the CRM) 24



Slide 25 Validation

certified concentration

Concentration

In the case of validation, a certified reference material can be used to verify the performance or accuracy of a given measurement method. Questions such as “is there any method specific bias?” or “is there any systematic error?” can easily be answered in this way. Thus this is another useful way of using a certified reference material. In the case shown here certainly there is a significant bias.

Check the measurement results in terms of validity: Is there any method specific bias ? Is there any systematic error ? 25



14


299

Slide 26 Measurement Control 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

(Upper) Warning line

-1s 0 1s 2s

(i.e. of proven homogeneity and stability; sometimes named in-house RMs or laboratory RMs)

(Upper) Control line

-2s

Abuse of CRM Instead: use in-house materials or quality control materials

-3s 3s

How about measurement control? Usually the measurement control process involves identical samples, which are introduced into the sample measurement sequence in order to monitor the stability of the system. Use of certified reference materials for this purpose is possible, but actually it is not an appropriate use of the material. It is better and more economical to use in-house materials of adequate homogeneity and stability (see chapter 13).

(Lower) Warning line (Lower) Control line 26



Slide 27 Thus summarizing the certified reference material should be used for calibration of an instrument or validation of a measurement method but preferably not used for measurement control.

Use of CRMs how can CRMs help my measurements? calibration (?) X YES validation (?) X YES measurement control (?) X NO

27



Slide 28 There is a lot of discussion about the How CRMs are Used in Terms of Traceability? use of certified reference material in n terms of measurement traceability. io at S.I. r Let’s see what is the influence for the li b a c to calibrate own two cases where the certified reference value 1 analytical instrument materials are useful in the laboratory value 2 (i.e. calibration and validation). In the case of calibration, the property value my result of the certified reference material is used to calibrate the analytical instrument used for the measurement, thus it is used in order to obtain the measurement result. In this way the property value of the certified reference material is part of the traceability chain, as shown in the slide, and is directly involved in the establishment of the measurement traceability. Papadakis, I .: (Certified) Referen ce Mater ial s In: W enclawiak, Koch, Hadj icostas (eds.)

28



300


Slide 29 In the case of validation, the property value of the certified reference material is not used to obtain the measurement result. It is only used to verify the performance of the analytical method. Thus it is not part of the traceability chain and it does not directly influence the establishment of measurement traceability.

How CRMs are Used in Terms of Traceability? io at id l va

n S.I. value 1

to validate own analytical method

value 2 my result

value CRM 29





Slide 30 There is a large number of certified Selection of CRMs reference materials available in the Availability (problem with matrix CRMs) market. It is of highest importance to Concentration range of certified property Uncertainty of certified property select an appropriate certified reference Traceability of certified property material for the intended use. There What is your uncertainty requirement are a number of criteria, which can be Contribution of CRM uncertainty on your measurement uncertainty used in order to select the appropriate Demonstrated competence of CRM producer certified reference material. Depending CRM matrix Cost on the measurement problem the importance of each criterion can vary. Experience and continuous use of certified reference material help to make a correct decision. Papadakis, I .: (Certified) Referen ce Mater ial s

30




Slide 31 A lot of information about certified reference material can be obtained from the COMAR database, but there is also a large amount of information in detailed catalogues of available products on the web-pages of individual certified reference material producers, which are usually large scientific establishments.

CRM Producers General COMAR database: http://www.comar.bam.de

Individual suppliers

IRMM: BAM: LGC: NIST: others...

http://www.irmm.jrc.be http://www.bam.de http://www.lgc.co.uk http://www.nist.gov

31



14


301

Slide 32 The general statement “I used a certified reference material, therefore my measurement result is correct” is very often used. This is an incorrect statement since when using a certified reference material there are still many things that can go wrong and which can result in an unreliable outcome.

General Statement

I use a CRM, therefore my measurement result is automatically correct

32



Slide 33 Summarizing this reference material chapter, you must remember that they are very important components for quality assurance in analytical laboratories. Their production is not an easy job, their selection and use requires specific information and careful decisions have to be made and finally the use of certified reference materials cannot replace careful laboratory work.

Things to Remember

Very important component Production is not trivial Selection and use is not easy CRMs do not automatically ensure quality outcome 33



Bibliography ISO Guide 30:1992 Terms and definitions used in connection with reference materials ISO Guide 31:2000 Reference materials – Contents of certificates and labels ISO Guide 32:1997 Calibration in analytical chemistry and use of certified reference materials ISO Guide 33:2000 Uses of certified reference materials ISO Guide 34:2009 General requirements for the competence of reference material producers ISO Guide 35:2006 Reference materials – General and statistical principles for certification

302


Zschunke A (2000) Reference Materials in Analytical Chemistry - A Guide for Selection and Use, Springer, Berlin Heidelberg

15

Interlaboratory Tests

Michael Koch Interlaboratory tests are one of the most important external quality assurance tools to assure comparability with all the other laboratories. Slide 1 For interlaboratory tests sub-samples are distributed to different laboratories for concurrent testing.

What are Interlaboratory Tests? Randomly selected sub-samples from a source of material are distributed simultaneously to participating laboratories for concurrent testing

1

Koch, M.: Interlabor ator y Tests In: W enclawiak, Koch, Hadj icostas (eds.)


Slide 2 There are different reasons for interlaboratory tests. One is method validation, e.g. prior to the standardization of characterization of reference materials, which have to be certified. The third and most important for quality assurance is proficiency testing of laboratories. There are different requirements for each type of interlaboratory test.

Types of Interlaboratory Tests

method validation

reference material characterization proficiency testing

2




303

304


Slide 3 The objective for interlaboratory tests for method validation is the best possible characterization of the method. Therefore it has to be assured that every participating laboratory uses exactly the same method.

Interlaboratory Tests for the Validation of a Method Objective: best possible characterization of the method Laboratories have to use exactly the same method Assistance should be given to assure this 3



Slide 4 Interlaboratory tests for characterization of a reference material are different. It is very important that only very experienced laboratories take part in this test to get the best possible estimation of the “true” value.

Interlaboratory Tests for Characterization of a Reference Material Objective: best possible estimation of the “true” value of the concentration Concentration of the analyte in the material must be analysed by experienced laboratories Less experienced laboratories should not be allowed to participate 4



Slide 5 The third type of interlaboratory tests is proficiency testing (PT) for laboratories. The objective here is to get an indication of the performance of the laboratory. The laboratory should work under routine conditions to get a realistic indication of its performance. A PT can not only be a help for the laboratory to improve its capabilities, but also can be used by customers or regulatory bodies for the selection of qualified laboratories.

Interlaboratory Tests for Proficiency Testing of Laboratories Objective: to get an indication of the performance of an individual laboratory or a group of laboratories as a whole Laboratories should work under routine conditions Help for the laboratory to improve its quality Can be used by customers or regulatory bodies for the selection of qualified laboratories 5



15


305

Slide 6 Interlaboratory tests are a test for accuracy. Inaccuracy arises from systematic and random effects that are related to bias and precision respectively. As a result of a PT the laboratory should be able to determine, whether imprecision or bias is the reason for its inaccuracy.

Objectives of Proficiency Tests Basic concern is accuracy Inaccuracy contains systematic and random effects Laboratory can determine, whether imprecision or bias is the reason for its inaccuracy 6



Slide 7 Why should a laboratory participate in PT schemes? First there is the possibility to uncover errors that couldn’t be found with other quality control measures and second a successful participation can be used as a certificate of competence for clients, authorities and accreditation bodies.

Motivation for the Laboratories To uncover errors that couldn’t be found with internal quality control Use as certificate for competence in this testing field for clients, authorities and accreditation bodies

7



Slide 8 However there are also limitations. First of all it takes time to evaluate a Limitations PT. So it is quite a long time before Interlaboratory tests are always retrospective the laboratory knows the result. The Organisation, distribution of samples, analyses, interlaboratory test is retrospective. It evaluation take time It is dangerous to rely only on interlaboratory tests is therefore not possible to base quality Proficiency tests cover only a small fraction of management only on proficiency tests. the often wide variety of analyses Proficiency tests do not reflect routine Normally PTs cover only a small part analyses of the laboratory’s business. This is the second limitation. A PT analysis normally does not reflect the routine analysis, because the effort given to the former can be much greater than the effort given to the latter.

8

Koch, M.: Interlabor ator y Tests




306


Slide 9 There are some guidelines on the Standards and Guidelines for requirements for proficiency testing Proficiency Testing - I schemes. The most important is the ISO/IEC 17043:2010 – Conformity new ISO/IEC 17043 “Conformity assessment – General requirements for assessment – General requirements for proficiency testing proficiency testing”. It describes the IUPAC, ISO, AOAC (2006): The International Harmonized Protocol for development and operation of a PT the Proficiency Testing of Analytical scheme with all quality management Chemistry Laboratories requirements related to that. The first version of the “International Harmonized Protocol for the Proficiency Testing of (Chemical) Analytical Laboratories was a result of a joint workshop of IUPAC, ISO and AOAC and was published in 1993. A 2nd , revised version was published in 2006. This protocol also sets out the requirements for the provider and for the PT scheme itself.

9





Slide 10 ILAC describes requirements for the Standards and Guidelines for competence of PT providers in its Proficiency Testing - II guideline G13. Due to the recent International laboratory accreditation publication of ISO/IEC 17043, a cooperation (ILAC-G13:2007): Guidelines for the requirements for the withdrawal of ILAC G-13 is to be competence of providers of proficiency expected. testing schemes. In ISO 13528 details on possible ISO 13528:2005 - Statistical methods statistical methods for the evaluation of for the use in proficiency testing by interlaboratory comparisons. proficiency tests are given. The following slides are mainly based on the content of these four guides and standards. Koch, M.: Interlabor ator y Tests


Slide 11 Since interlaboratory tests are a great logistical challenge, especially if there are a lot of participants, the personnel of the provider must have special organizational capabilities. To understand the problems associated with the analyses there must be technical

10



Demands on the Provider Personnel

Special organisational capabilities Technical experts for the analysis Statisticians All staff have to be competent for the work it is responsible for

11



15


307

experts as well as statisticians involved in the evaluation. As in a good laboratory everybody has to be competent in the work for which he is responsible. Slide 12 It should be a matter of course carefully to prepare an interlaboratory test. This includes the documentation of the plan before the start of the test.

Demands on the Provider – Planning The interlaboratory test should be carefully prepared. The planning must be documented before the start of the test

12



Slide 13 The minimum content of this plan is listed in the next three slides.

Demands on the Provider – PT Plan - I Name and address of the PT provider Name, address and affiliation of the coordinator and other personnel Activities to be subcontracted and the names and addresses of subcontractors Criteria to be met for participation Number and type of expected participants Selection of the measurand(s) or characteristic(s) of interest, including information on what the participants are to identify, measure, or test for Description of the range of values or characteristics, or both, to be expected for the PT items Potential major sources of errors involved in the area of PT offered Koch, M.: Interlabor ator y Tests In: W enclawiak, Koch, Hadj icostas (eds.)

13


Slide 14 Demands on the Provider – PT Plan - II Requirements for the production, quality control, storage and distribution of PT items Reasonable precautions to prevent collusion between participants or falsification of results Description of the information which is to be supplied to participants and the time schedule for the various phases of the PT scheme Information on methods or procedures which participants need to use Methods to be used for the homogeneity and stability testing 14



308


Slide 15 Demands on the Provider – PT Plan - III Standardized reporting formats to be used by participants Detailed description of the statistical analysis Origin, metrological traceability and measurement uncertainty of any assigned values Criteria for the evaluation of performance Description of the data, interim reports or information to be returned to participants Description of the extent to which participant results are to be made public Actions to be taken in the case of lost or damaged proficiency test items 15



Slide 16 The data-processing equipment used by the provider also has to be fit for the purpose. This includes hardware as well as adequate software, which have to be verified and backed up.

Demands on the Provider – Data-processing Equipment Equipment should be adequate for Data processing Statistical analysis To provide timely and valid results

Software must be Verified and Backed up 16



Slide 17 The selection and preparation of the samples very often is the most crucial item in an interlaboratory test. All characteristics that could affect the integrity of the test have to be considered. This includes homogeneity and stability, which are dealt with in detail later. The PT provider has to look for possible changes in and the effect of ambient conditions on the samples.

Demands on the Provider – Test Item Preparation and Management - I For the selection of the test item all characteristics that could affect the integrity of the interlaboratory comparison should be considered

Homogeneity Stability Possible changes during transport Effects of ambient conditions (e.g. temperature) 17



15


309

Slide 18 The samples that are used for Demands on the Provider – Test Item proficiency tests should be similar to Preparation and Management - II routine samples in order to get an Samples used in the proficiency test information about the routine capabilishould be similar to the samples that ties of the laboratory. In some cases it are routinely analysed in the laboratories is useful to distribute a larger amount Sample amount of sample than is needed for the Surplus of sample can be used as reference material determination, to give the laboratories Surplus can be used to make excessive the opportunity to use this material as effort on the analyses an in-house reference material. But the surplus can be also used to carry out more analyses compared to routine, which is not desired. Koch, M.: Interlabor ator y Tests


18



Slide 19 The PT provider has to take care that all the distributed samples are comparable with each other. Therefore the provider has to ensure the homogeneity of the testing material before dividing it into sub samples. The provider must have a documented procedure for homogenisation and for homogeneity tests. It has to be assured that the evaluation of the laboratory results is not affected by inhomogeneities.

Demands on the Provider Homogeneity - I The PT provider has to ensure that every laboratory will receive samples that do not differ significantly in the parameters to be measured Documented procedure for establishing this homogeneity Degree of homogeneity Î evaluation of the laboratories results must not be significantly affected

Any variation between the portions must be negligible in relation to the expected variations between the participants 19



Slide 20 This is easier for true solutions, because they are homogeneous at a molecular level. For solid samples this is more difficult and special methods must be applied to ensure homogeneity. A procedure using ANOVA techniques for the check for homogeneity is described in the International Harmonized Protocol.

Demands on the Provider Homogeneity - II True solutions are homogeneous at a molecular level For solid samples Î special care on the homogenisation A homogeneity check on the basis of ANOVA is described in the „International harmonized protocol...“ 20



310


Slide 21 Another requirement for the PT samples is stability under the PT conditions for the time period between the sample production and the analyses in the laboratory, which has to be assured and tested by the PT provider.

Demands on the Provider Stability - I Test material must be sufficiently stable Under the conditions of storage and distribution to the participants For the time period from producing the samples until the analyses in the participant’s laboratory

This stability has to be tested by the PT provider 21



Slide 22 The only way to test it is by making a Demands on the Provider repeat measurement after the estimated Stability - II time necessary for the sample distribu Analysing a part of the samples after the tion has expired. There are two possible estimated time necessary for the distribution Differences in the results may be due to instability explanations for differences in the or to between-batch variability in the organiser’s laboratory result: Information may be derived from the instability and organiser’s prior experience or obtained from technical literature between-batch variability of the Accelerated stability testing by worsening the provider’s analyses. ambient conditions for the samples Further information on stability can be derived from the provider’s experience or from literature. It might also be necessary to perform accelerated tests under worst-case conditions. Koch, M.: Interlabor ator y Tests


22



Slide 23 The PT provider has to assure that the changes in the samples are negligible and do not affect the evaluation of the laboratory performance.

Demands on the Provider Stability - III The organiser has to ensure that the changes due to instability do not significantly affect the evaluation of the laboratories’ performance

23



15


311

Slide 24 Normally the laboratory should use its routine method for the analysis of the PT samples, but there might be legal regulations that limit the choice of methods. In order to conduct a method-specific evaluation and to be able to comment on the results of different methods, the PT provider should ask for the details of the method used.

Choice of Analytical Method Normally the laboratory should use its routine method The choice might be limited by e.g. legal regulations Organiser should ask for details To conduct a method specific evaluation To give comments on the methods used 24





Slide 25 A method-specific evaluation might look like that shown in this slide. The Method Specific Evaluation results obtained with the different methods are divided into five classes. Results which are between the range “assigned value” (av) ± 1 s, are in the class titled “correct”, the range av + 1s < x ≤ av + 2s is titled “high” and x > av + 2s “too high”. A similar classification is made for “low values”. In this figure differences between different methods can easily be seen. But methods that show deviations like the photometry in the example are not necessarily bad methods. The example shows that there are more sources for possible mistakes. The consequence is that these mistakes are made by a number of analysts. But it definitely is possible to measure correct results with this method. aluminum in groundwater

ICP-MS GFAAS

80

ICP-OES

70

Photometry

60 50 40 30 20 10

0

too low

low

correct

high

too high

25



Slide 26 The performance of the laboratories is measured against the assigned value, which therefore is very important. This value has to be determined very carefully. If the assigned value is inappropriate the whole PT scheme is questionable. In principle it is the same



Determination of the Assigned Value One of the most critical features of a proficiency test Inappropriate value will drastically reduce the value of the scheme The same problem as in the certification of a reference material But the organiser of a proficiency test cannot expend the same amount of effort 26



312


problem as the determination of the value of a reference material. However if the PT provider were to spend the same effort in the determination of the assigned value, the PT scheme would be much too expensive. In some cases it would not be possible to carry out such a detailed determination of the assigned value, because the samples are not stable enough for such a long procedure. In the following slides various possibilities for the definition of the assigned value are shown. Slide 27 A CRM is an ideal test material for a PT scheme. Unfortunately their high cost and lack of availability of suitable CRMs in the quantity and concentration range needed limit their use. Very often a PT scheme has to deal with more or less unstable samples to meet the laboratories’ requirements. In this case CRMs are very unlikely to be available.

Assigned Value – Certified Reference Material Ideal test material for a proficiency test Disadvantages High costs Limited availability In the necessary quantity And concent ration range

CRM‘s have to be stable for months and PT often deals with more or less instable samples (foodstuffs, biomedical, environmental samples) 27



Slide 28 Another possibility is to choose expert laboratories, which are able to measure with high precision reference methods, utilising traceable calibration materials. If these laboratories use methods based on different physico-chemical principles and come to more or less the same result, it is very probable that the value is close to the “true” value.

Assigned Value – Consensus of “Expert Laboratories” - I Mean of analysis by expert laboratories With high precision reference methods and traceable materials for calibration If different physico-chemical methods are used and the same results are obtained, it is more probable that the value is near to the „true“ value 28



15


313

Slide 29 There are two disadvantages with this method. On the one hand much effort is required to ensure the accuracy of the reference measurements. This is a matter of capacity in the reference laboratories and a matter of costs as well. On the other hand there might be doubt among the participants about the assigned value, because “nobody is perfect”. This is especially true if the mean of the participants’ results deviates from the assigned value.

Assigned Value – Consensus of “Expert Laboratories” - II Disadvantages Very much effort to ensure the accuracy of the reference measurements “Nobody is perfect” There might be doubts among the participants if the result of the expert laboratories deviates from the mean of the participants

29



Slide 30 Assigned Value – Formulated or

Another method is spiking of materials “Synthetic” Test Materials - I with a known amount of the analyte. Materials, spiked with the analyte to a known extent This can be done with high precision Can be made with extremely accurate amounts by by gravimetric or volumetric methods. gravimetric or volumetric methods If material does not contain significant If there is no analyte in the base amounts of the analyte material the assigned value can be Assigned value directly from added amount calculated directly from the added If material contains analyte, this amount has to be characterized very well. amount. If the material already contains a certain amount of analyte, this amount has to be quantified with sufficient accuracy. Koch, M.: Interlabor ator y Tests


30



Slide 31 Assigned Value – Formulated or

The disadvantages of this method are “Synthetic” Test Materials - II the difficulty of achieving sufficient Disadvantages homogeneity. Especially if the Difficult to achieve sufficient homogeneity, especially with solid materials samples are solid materials (e.g. soil or Analyte might be bound in a different foodstuff) this could be a significant chemical form Especially in solid materials the originally problem. The second point is that the contained analyte might be bound more analyte originally contained in the strongly to the matrix material might be more tightly bound to the matrix than the added analytes. Then the recovery of the spiked analyte could be much better than that of the originally bound analyte. Koch, M.: Interlabor ator y Tests


31



314


Slide 32 The easiest and cheapest, and therefore most often used method is to take a consensus value of the participants as the assigned value. If the analysis being tested is very easy and straightforward to perform, then this is not a problem since the assigned value will be a good estimate for the “true” value. For “conventional methods” this is the only possibility because the “true” value in this case is defined by the analytical procedure.

Assigned Value – Consensus of Participants - I Easiest and cheapest way Î used very often If method for analysis is easy and straightforward Î good estimate of „true“ value If a „convention method“ (an empirically defined method) is used, the consensus value is the only possibility 32



Slide 33 Assigned Value –

But this method also has disadvantages. Consensus of Participants - II The consensus value could be seriously Disadvantages biased, if the majority of the participants Consensus value might be seriously biased (e.g. analyses of highly volatile substances) have biased values in the same direc There might be no consensus at all E.g. if two analytical methods are used, where one is tion, which could be the case e.g. in the biased These circumstances are not uncommon in trace analyses of highly volatile substances. analysis Or there might be no real consensus at Care should be taken to decide whether a consensus value really is good choice all. This could perhaps result from the use of two different methods, where one is biased. All of these are common in trace analysis and therefore a participants’ consensus is not always a good way for defining the assigned value. Koch, M.: Interlabor ator y Tests


Slide 34

33



Methods to Calculate Consensus Value – Arithmetic Mean

If a consensus value is used as the Requires an outlier test assigned value there are different But these tests are often not very satisfactory, especially if many outliers are possibilities to calculate it. If the present arithmetic mean is used, an outlier test Outlier tests assume normal distribution which is normally not true in trace analysis is required. But in many cases these tests are not very satisfactory, especially if several outliers are present. If the tests are strictly used, they can only be applied to normally distributed data, which is usually not the case in trace analysis. Koch, M.: Interlabor ator y Tests


34



15


315

Slide 35 The median is not affected by outlying data, but the statistical efficiency is not good. This means that the reliability of the estimation of a dataset’s population mean from a small sample of data is lower than for the other methods.

Methods to Calculate Consensus Value – Median Not affected by outlying data Low statistical efficiency

35



Slide 36 “Robust Statistics” use trimmed data Methods to Calculate Consensus for the calculation of the estimated Value – Robust Mean values. That means, that a part of the “Trimmed” data; a certain part of the data on both tails of the data set is data set in the tails is excluded or excluded prior to the calculation of the modified prior to or during the calculamean tion. An easy example is the use of the E.g. mean of interquartile range Mean of data between the first and the interquartile range (the range between third quartile of the data set the first and the third quartile) instead Or algorithm A of the whole data set. Special methods have been developed in the past e.g. by Huber (algorithm A) and Hampel. Koch, M.: Interlabor ator y Tests


36



Slide 37 Methods to Calculate Consensus The calculation of a robust mean Value – Robust mean – Algorithm A according to a method introduced by Iterative process Huber and described in the relevant Described in ISO 5725, ISO 13528 and the International Harmonized Protocol standards is shown in this slide. The Define initial value for m as median of all data method starts with median as the initial All data outside m ± 1.5 • STD are set to m + 1.5 • STD or m - 1.5 • STD value m for an iterative procedure. All New value for m is calculated as arithmetic mean of the new data data outside the m ± 1.5*STD are set Repeat until there are no changes to this border. Then a new value for m is calculated from the arithmetic mean of this new data. The procedure of transforming the initial data outside the range m ± 1.5*STD and calculation of a new mean is then repeated until there are no more changes in the values. Koch, M.: Interlabor ator y Tests


37



316


Slide 38 In the last years the robust statistical methods got more and more important. In all new relevant standards the use of these methods are now highly recommended.

Choice of Method to Calculate Consensus Value The use of robust methods (e.g. algorithm A) is highly recommended in all relevant standards

38



Slide 39 Once the assigned value is set the target value for the analyses is known. But it is also necessary to define a tolerance range for the analytical results. Values within this range are considered as satisfactory. This range might originate from a “fitness for purpose” requirement or it might be calculated from the dispersion of the data, i.e. from the standard deviation.

Performance Scoring Assigned value is the target For the assessment of laboratories a accepted range is necessary Prescribed range originating from the demands put on the analysis (fitness for purpose) Calculated from the standard deviation of the data set 39



Slide 40 Provided that the data are normally distributed, 95.5% of the values will lay within the range µ ± 2σ, and 99.7% within µ ± 3σ. That means in other words that on a confidence level of 95.5% all accurate data are inside µ ± 2σ.

Performance Scoring – Tolerance Range from STD Normally distributed set of data 95,5% of the values inside a range of ± 2σ 99,7% of the values inside a range of ± 3σ

On a confidence level of 95,5 % all accurate data are inside µ ± 2σ

40



15


317

Slide 41 For proficiency tests z-scores have been widely used for many years. Z-scores represent the deviation from the assigned value in standard deviation units. The standard deviation may be calculated after exclusion of outliers or with robust statistics. In some cases it is set to a certain value according to the quality targets of the PT provider.

Performance Scoring – Z-score The deviation from the assigned value in standard deviation units

z − score =

(x − μ) s

The standard deviation is calculated after exclusion of outlier or with robust statistics 41



Slide 42 In the International Harmonized Protocol z-scores are classified into three categories. The range –2.0 to +2.0, corresponding to a confidence level of 95.5% is classified as satisfactory. The range 2.0 < |z-score| < 3.0 is classified as questionable since the probability that these data are accurate is only 4.5%. Data with |z-score| ≥ 3.0 are classified as unsatisfactory, because the confidence level is only 0.3%.

Performance Scoring – Classification in the Internat. Harmonized Protocol |z-score| ≤ 2.0 - satisfactory 2.0 < |z-score| < 3.0 - questionable |z-score| ≥ 3.0 - unsatisfactory Z-scores are common practise in the assessment of laboratory results 42



Slide 43

Z-score - Diagram 10 5 Z-score

If the z-scores of the participants for a specific sample are sorted and depicted in a bar chart they normally show a typical S-shape. In this diagram the existence of a real consensus value can easily be seen. This figure also enables the participants to compare their results with their peers.

0 -5 -10 -15

75 39 40 36 34 20 71 56 3 85 2 59 43 25 54 90 1 80 44 76 64 29 79 73 15 7 57 32 37 72 52 10 17 95 63 49 4

laboratory code 43



318


Slide 44 The concept of z-scores is based on the assumption that the data are Statistical distribution normally distributed. But this is not Data near to the limit of determination true for data near the detection limit. are not normal distributed The distribution has to be skewed; Otherwise there should be negative otherwise there would be a finite values with a finite probability probability of negative values. For this Tolerance limits should be asymmetrical (more narrow below the assigned value, reason tolerance limits should also be more wide above it) asymmetrical. If they are narrower below the assigned value, this also ensures that the lower tolerance limit will not be negative with the consequence that all data delivered with “< X” would have to be classified as acceptable. 44





Slide 45 Two approaches attempt to solve this problem. The one is a transformation of the data to logarithms prior to the statistical calculations corresponding to a logarithmic normal distribution. The other is a modification of the z-scores with correction factors. This method was introduced first in a German standard for proficiency testing (DIN 38402 – 45), which in the meantime partially was transferred into ISO/TS 20612.

Solution Approaches for Asymmetrical Tolerance Limits Logarithmic normal distribution Take the logarithm of the values prior to statistical calculations

Modification of Z-scores ⎧g ⋅ Z if Z < 0 ⎪⎪ k Zu = ⎨ 1 g ⎪ ⋅ Z if Z > 0 ⎩⎪ k 2

with g = quality limit for Z and k1, k2 =correction factors

1⎞ 1⎞ ⎛ ⎧ 1 2⎫ ⎛ ⎧ 1 2⎫ ⎜ k 2 + ⎟ exp ⎨− k 2 ⎬ = ⎜ − k1 + ⎟ exp ⎨− k1 ⎬ ν⎠ ν⎠ ⎝ ⎩ 2 ⎭ ⎝ ⎩ 2 ⎭

⎛ ⎛ 1 ⎞⎞ ⎜⎜1 − Φ⎜ − ν ⎟ ⎟⎟ ⎝ ⎠⎠ ⎝

−1

(Φ(k2 ) − Φ(− k1 )) = 1 − α

ν = rel. standard deviation Φ = distribution function of standard normal distribution 1-α = confidence level (here: 0,955)

(from ISO/TS 20612:2007) 45



Slide 46 The aim of a proficiency test is normally, not only to assess single values, but also to get an impression of the performance of the laboratory as a whole. If the laboratory is assessed by combinations of the assessments of the single values only, this involves the danger of misinterpretation. This is

Laboratory Assessment By combination of single value assessment Involves danger of misinterpretation A laboratory can measure one parameter permanently wrong, but nevertheless is positively assessed

46



15


319

because a laboratory can measure some of the parameters incorrectly all the time yet be positively assessed. Slide 47 In the International Harmonized Protocol two possibilities for Combined Assessment According to combined assessments are specified. Intern. Harmon. Protocol... - RSZ For the rescaled sum of z-scores a RSZ (rescaled sum of z-scores) combination of the z-scores is RSZ = Σz/√m with m = number of scores Same scale as z-score calculated from RSZ=Σz/√m with Negative assessment, if all values are m=number of z-scores. This RSZ has within the tolerance but a little biased in the the same scale as a z-score. But if all same direction Errors with opposite sign cancel each other values are biased to the same direction, out still being within the tolerance limits, this will lead to a negative total assessment. On the other hand if the values are biased in different directions, this improves the total assessment. Koch, M.: Interlabor ator y Tests


47



Slide 48 The sum of z-scores SSZ=Σz² has a different scale, but doesn’t consider the sign of the z-scores.

Combined Assessment According to Intern. Harmon. Protocol... - SSZ SSZ (sum of squared z-scores) Different scale, because Χ2-distributed Does not consider the sign of z-scores

48



Slide 49 Nevertheless in most PT schemes a combination of single value assessment is used, just counting positive and negative assessments of all values. This does not consider the value of the z-score. In the PT scheme of the German water authorities the following limits are

Combination of Single Values Assessments Just counting positive and negative assessments of all values The absolute value of the z-score is not considered E.g. assessment in the proficiency tests of German water authorities 80 % of the values – |Zu-score|≤2 80 % of the parameters successful 49



320


used for a positive total assessment: The tolerance limit for single values are set to |zU-scores| ≤ 2, 80% of the values have to be inside the tolerance limits, and 80% of the parameters have to be analysed successfully, meaning more than 50% of the values for this parameter are positively assessed. Slide 50 When the proficiency test is finished the PT provider has to report the results to the participants. This should be done as soon as possible, i.e. normally not later than 1 month after the deadline for the return of the analytical results, to give a quick feedback to the participants. This enables the laboratories to react and take corrective actions. To maintain confidentiality, only a code should be used to identify the laboratory in the report. Slide 51 The necessary content of a test scheme report is listed in ISO/IEC 17043 in detail and shown here in the next three slides.

Test Scheme Reports Should be distributed to the laboratories as soon as possible Normally not later than 1 month after deadline for the analytical results Laboratories need quick feedback for corrective actions

Laboratories should be identified in the report by test specific codes to maintain confidentiality 50



Test Scheme Reports – ISO/IEC 17043 – Contents - I Name and contact details for the PT provider Name and contact details for the coordinator Name, function and signature of person authorizing the report Indication of which activities are subcontracted by the PT provider Date of issue and status (e.g. preliminary, interim, or final) of the report Page numbers and a clear indication of the end of the report Statement of the extent to which results are confidential Report number and clear identification of the PT scheme 51



Slide 52 Test Scheme Reports – ISO/IEC 17043 – Contents - II Clear description of the PT items used, including necessary details of the PT Item's preparation and homogeneity and stability assessment Participants' results Statistical data and summaries, including assigned values and range of acceptable results and graphical displays Procedures used to establish any assigned value; Details of the metrological traceability and measurement uncertainty of any assigned value Procedures used to establish the standard deviation for proficiency assessment, or other criteria for evaluation Koch, M.: Interlabor ator y Tests In: W enclawiak, Koch, Hadj icostas (eds.)

52


15


321

Slide 53 Test Scheme Reports – ISO/IEC 17043 – Contents - III Assigned values and summary statistics for test methods/procedures used by each group of participants (if different methods are used by different groups of participants) Comments on participants' performance by the proficiency testing provider and technical advisers Information about the design and implementation of the PT scheme Procedures used to statistically analyse the data Advice on the interpretation of the statistical analysis Comments or recommendations, based on the outcomes of the PT round Koch, M.: Interlabor ator y Tests In: W enclawiak, Koch, Hadj icostas (eds.)

53


Slide 54 The participants in most schemes are interested in getting a certificate of successful participation in order to use it for advertising and demonstration of competence to their customers.

Certificate If the proficiency test scheme has regulations for the assessment of the laboratories on the basis of the data (successful / not successful) a certificate should be sent to the laboratory in case of successful participation. In many cases these certificates are used by the laboratories for demonstrating competence to their customers, i.e. for advertising. 54



Slide 55 This slide shows an example from a German PT scheme.

Certificate – Example

55



322


Slide 56 For most laboratories it is essential Confidentiality that their identity in a proficiency test Normally in all PT schemes the identity of all laboratories are kept confidential is kept confidential, because public Public reports about poor performance of a reports about poor performance could laboratory in a proficiency test could be the economic ruin of this laboratory ruin a laboratory. In the PT provider Identity should be known only to a small organization the identity of the laboranumber of persons These persons must be regularly instructed about tories should also be known only to a there duty to keep this information confidential The coordinating body may be required to small number of persons, who must be report poor performance to a particular regularly instructed about their duty to authority Participants should be notified of this possibility keep this information confidential. The provider may be required to report the performance of the laboratories to an authority. In this case the participants have to agree upon this procedure prior to participation. Koch, M.: Interlabor ator y Tests


56



Slide 57 Proficiency tests first of all should help the laboratories improve their performance. But often they are also used as a control tool for accreditation bodies, customers and authorities. Thus, there may be a tendency among some participants to try to report a better performance than is justified.

Collusion and Falsification of Results PT schemes often are not only a help for the laboratories to improve their quality but also a control tool for accreditation bodies, customers and authorities There may be a tendency among some participants to give a falsely optimistic impression of their capabilities 57



Slide 58 Collusion between participants must not be possible. Distributing as many concentration levels, i.e. different samples, as possible to confuse potential cheats, can help to prevent this.

Collusion Must not be possible

As many concentration levels as possible 58



15


323

Slide 59 PT samples normally should be analysed with the same effort as Number of Multiple routine samples. But in reality this Measurements very rarely is the case. An example is Example from reality: shown in this slide, where a double Routine: single measurement Asked in proficiency test: measurement was requested in the independent double measurement proficiency test. During an accreditation Executed in proficiency test: assessment it was found that the 40 (!) measurements Therefore: limitation of sample amount, laboratory executed 40 measurements where possible to be sure of the value. Where possible, limiting the sample amount to that necessary for duplicate measurements can help prevent this. Koch, M.: Interlabor ator y Tests

59




Slide 60 Level-by-level Evaluation for Different Concentrations Can lead to injustice aluminium

tolerance limits / standard deviation in %

Usually different levels and different samples in proficiency tests are evaluated separately. This can lead to injustice if by chance good laboratories are grouped together in one concentration level and less good laboratories in another. This results in variations in the tolerance limits as shown in this slide. A calculation procedure for a variance function was introduced in the German standard DIN 38402-45 and also published in ISO/TS 20612.

120 100 80 60 40 20 0 -20 -40 -60 -80 0,050

0,075

0,100

0,125

0,150

0,175

0,200

concentration in mg/l

A procedure for a common evaluation can be found in ISO/TS 20612:2007 60



Slide 61 What is the effort required for a laboratory to participate in a proficiency test? First it is the effort to analyse the sample, which should not exceed the effort for routine samples but in reality it is not insignificant. Second it is the participation fee that the laboratory has to pay.

Effort for the Laboratory Analysis of the samples Should not exceed the effort for routine samples In reality not insignificant

Participation fee

61



324


Slide 62 The participation fee usually is in the range of 300 US-$ and 1000 US-$ depending mainly on the matrix and the parameters that have to be analysed.

Participation Fee Normally between 300 US-$ and 1000 US-$ (depending on matrix and parameters)

62



Slide 63 But there are a lot of benefits for the participants, which are listed in the next three slides.

Benefits - I Regular, external and independent check on data quality Assistance in demonstrating quality and commitment to quality issues Motivation to improve performance Support for accreditation/certification to quality standards Comparison of performance with that of peers 63



Slide 64

Benefits - II Assistance in the identification of measurement problems Feedback and technical advice from organisers (reports, newsletters, open meetings) Assistance in the evaluation of methods and instrumentation A particularly valuable method of quality control where suitable reference materials are not available Koch, M.: Interlabor ator y Tests In: W enclawiak, Koch, Hadj icostas (eds.)

64


15


325

Slide 65

Benefits - III Assistance in training staff Assistance in the marketing of analytical services Savings in time/costs by reducing the need for repeat measurements A guard against loss of reputation due to poor performance Increased competitiveness 65



Slide 66 Weighing up costs and benefits, the costs are noticed immediately and the benefits are difficult to quantify, least of all in monetary terms. But the participation in PT schemes often is an important proof of competence and therefore more than compensates the cost of participation.

Benefits - Costs The costs are noticed immediately Benefits are difficult to quantify in monetary terms The successful participation often is a important proof of competence And therefore compensate for the costs of participation 66



Bibliography Huber PJ (1981) Robust statistics. Wiley, New York International laboratory accreditation cooperation (2007) G13 – ILAC Guidelines for the requirements for the competence of providers of proficiency testing schemes, available from http://www.ilac.org ISO 13528:2005 - Statistical methods for use in proficiency testing by interlaboratory comparison ISO/IEC 17043:2010 - Conformity assessment — General requirements for proficiency testing ISO/TS 20612:2007 - Water quality — Interlaboratory comparisons for proficiency testing of analytical chemistry laboratories Koch M, Baumeister F (2008) Traceable reference values for routine drinking water proficiency testing: first experiences. Accred. Qual. Assur. 13, 77-82

326


Koch M, Metzger, JW (2001) Definition of assigned values for proficiency tests in water analysis. Accred. Qual. Assur. 6, 181-185 Lawn RE, Thompson M, Walker RF (1997): Proficiency testing in analytical chemistry. Royal Society of Chemistry for the Laboratory of the Government Chemist (LGC), Teddington Rienitz O, Schiel D, Güttler B, Koch M, Borchers U (2007) A convenient and economic approach to achieve SI-traceable reference values to be used in drinkingwater interlaboratory comparisons. Accred. Qual. Assur. 12, 615-622 Thompson M, Ellison SLR, Wood R (2006) The international harmonized protocol for the proficiency testing of analytical chemistry laboratories. Pure Appl. Chem. 78, 145-196

For viewing supplementary electronic material on www.extras.springer.com/2010/978-3-642-13608-5, you need the following password: Qa13608#

Index A acceptance zone 268 accommodation 35, 151 accreditation 5, 19, 73 accreditation body 20 accuracy 5, 172, 228, 233, 313 action limit 278, 280 affinity diagram 128 algorithm A 315 alternative hypothesis 174 amendments 157 analyte 225 analytical function 187 analytical method 314 ANOVA 309 APLAC 4 apparatus 105 arithmetic mean 164, 315 assessment 325 assigned value 308, 326 audit 6 authority 52 authorization 35 average run length 282

B base quantities 207 basic calibration 187 benchmarking 128 between-batch condition 276 bias 6, 224, 234, 264 BIPM 2, 3 blank sample 285 blank value chart 285 brainstorming 129

C calibration 183, 287, 301, 312 calibration certificate 41 calibration curve 13 calibration function 187 cause and effect diagram 129 certificate 305, 321 certification 6, 73 certified reference material 37, 210, 221, 237, 262, 289, 294, 301, 312 changes of documents 156

CITAC 4 collusion 322 COMAR 300 combined standard uncertainty 16, 253, 264 combined uncertainty 254, 257 commitment 144 communication 53 competence 78 complaints 31, 153 compliance assessment 271 confidence limit 171 confidentiality 320 conformity assessment 76 consensus 317 continual improvement 69, 145 continuous improvement 114, 118 control charts 130, 266, 281 control of measuring device 64 control of production 62 control of records 32 control sample 287 conventional method 314 conventional true value 11 corporate objectives 118 corrective action 31, 69 correlation coefficient 189 cost of conformance 136 cost of non-conformance 136 cost of quality 113, 136 coverage factor 16 critical value 195 CRM see certified reference material CRM production 305 Crosby 132 cumulative distribution 163 customer 84 customer communication 58 customer focus 50 customer property 63 customer satisfaction 116 cusum control chart 281

D data collection form 128 decision rule 271 defect equipment 152 defective products 139

328

Index

degree of validation 223 Deming 133 derived quantities 207 design and development 58 difference chart 285 distribution 163, 164 document approval 154 document control 28, 29, 154 document issue 154 documentation 241

E ell 206 environmental conditions 35, 151 equipment 37, 152 error 15, 172 etalon 291 EURACHEM 4, 43, 79, 224, 244, 253 EUROLAB 4, 79 European Co-operation for Accreditation 4, 20 ExcelKontrol 283, 284 expanded uncertainty 16, 257, 261, 264, 268 expert laboratories 313 external calibration 184

F facility 104 failure 136 false negative 15, 195 false positive 15, 195 falsification 322 fishbone diagram 255 fit for the purpose 7, 219, 245, 276, 286 flowchart 130 fortified material 237 F-test 178, 190, 191

G geometric mean 165 Glossary 1 GLP see good laboratory practice GLP principles 99 good laboratory practice 23, 95 GUM 253

H handling 39 harmonic mean 165 histogram 131, 162 homogeneity 188, 307, 308, 313, 320 homogeneity of variances 190 human resources 55

I identification 63 identity 225, 226 IEC 1 IFCC 2 ILAC see International Laboratory Accreditation Cooperation importance of measurement 204 improvement 31, 124 incurred material 238 ineffective movements 140 ineffective procedures 140 influence quantity 7 infrastructure 55 in-house reference material 286, 309 instrument validation 12 interlaboratory comparison 264, 266 interlaboratory test 153, 233, 286 intermediate precision 236 internal audit 32, 66, 152 internal communication 53 internal quality control 9 internal standard 185, 193 International Harmonized Protocol 315, 317, 312, 326 International Laboratory Accreditation Cooperation 4, 20, 79, 325 International System of Units 3, 38, 207 interquartile range 315 IRMM 4 Ishikawa 129, 134, 255 ISO 1 ISO 5725 239 ISO 8466 186 ISO 9000 45 ISO 9001 23, 45, 84 ISO 9004 45 ISO guide 35 301 ISO guides 301 ISO/IEC 17011 20 ISO/IEC 17025 19, 87, 143, 144, 250, 271, 274 ISO/IEC 17043 320, 325 ISO-ILAC-IAF Communiqué 91 IUPAC 1 IUPAP 2

J Juran 134

K kurtosis 168

Index

329

L

O

lack of standard 206 legal responsibility 24 limit 270 limit of detection 12, 193, 223, 224, 228 limit of quantification 13, 193, 198, 224, 228 limit of Quantification 228 linear calibration 188 linear function 186 linear least squares calibration 13 linear regression 186 linearity 13, 189, 190, 229 list of signatures 148

obsolete documents 156 OECD 95 OIML 2 one-sample t-test 177 one-tailed question 177 opinions and interpretations 41 organization 24 organization chart 147 organizational structure 120 outlier 191 out-of-control 284 overproduction 138

M

P

management commitment 50 management representative 52 management requirements 24 management responsibility 49 management review 32, 53, 153 Mandel-test 190 Mars Climate Orbiter 203 master list 155 materials 105 mean control chart 278 measurand 14 measurement 14, 206 measurement method 14 measurement of performance 121 measurement procedure 14 measurement result 14 measurement standard 14, 291 median 165, 315 Meter Convention 208 method 225 method development 227 method validation 12, 304 method-specific evaluation 311 metrology in chemistry 205 minimum detectable concentration 12 mode 165 mole 209 monitoring and measurement 66 mutual acceptance 96

paired t-test 180 Pareto 131 Pareto diagram 131 partial derivation 256 participation fee 324 performance 325 performance characteristics 223 personnel 34, 100, 103, 307 plan 308 Plan-Do-Check-Act 121, 133 planning 51 policy 114 population 164 population mean 12 precision 7, 172, 220, 228, 234, 239, 242 pre-period 283 prevention 136 preventive action 31, 70 principles of GLP 101 probability 170 problem identification 118 problem solving 124 procedures 48, 145 process 114 process approach 46 process management concept 120 process measurement 117 product realization 56 product requirements 58 proficiency testing 12, 240, 321 provision of resources 54 PT result 266 purchasing 30, 60

N New Approach 75 NIST 4 non-clinical safety testing 97 non-conformity 31, 68 NORDTEST 266 normal distribution 168, 318 null hypothesis 174

Q quadratic function 186 qualified guess 256 quality 8

330

Index

quality assurance 9 quality assurance personnel 103 quality assurance programme 103 quality control 9, 113, 135, 242 quality improvement 123, 135 quality loss 127 quality losses 116 quality management 145 quality management system 26, 45, 89 quality manager 147 quality manual 26, 27, 48, 143 quality objectives 48 quality planning 135 quality policy 26, 48, 51, 146

R r%-chart 280 range chart 284 r-chart 280 reagents 105 real sample 286 records 49 recovery 231, 233, 234 recovery experiment 263 recovery rate chart 284, 285 rectangular distribution 256 reference item 106 reference material 151, 283, 302, 312 reference material producer 301 reference method 232 rejection zone 270 relative standard deviation 167 reliability 88 repeatability 228, 234, 262 repeatability limit 236 report 39, 109, 324 reproducibility 225, 236, 262 reproducibility limit 236 reproducibility standard deviation 266 residual analysis 190 residual standard deviation 188, 189 resource management 54 responsibility 52, 145, 148 retention of records 110 review input 53 review of requests, tenders and contracts 29 review of the documents 29 review output 54 robust statistics 165, 325 robustness 225, 237 role 145 RSZ 319 ruggedness 237

S sample 164 sampling 38 scatter diagram 132 scope 23 second order calibration 189 selectivity 225, 226 sensitivity 225, 237 sensitivity coefficient 256 service to the customer 30 Shewhart 282 SI see International System of Units signal-to-noise ratio 197 significance testing 173 skewness 167 software 308 specification limit 250 specification of the measurand 254, 258 spike 285 spiked material 237 SSZ 319 stability 188, 297, 299, 310, 320 staff 148 standard 10 standard addition 185 standard addition method 198 standard deviation 166, 238, 276 standard deviation of the mean 167 standard operation procedure 101, 107, 149 standard solution 284 standard uncertainty 16, 256 standards 3 statistics 161 stocks 139 storage of records 110 strategy 114 study 100 study director 102 study performance 108 subcontracting 30 synthetic sample 286 systematic error 279

T target control chart 284 target value 281 technical barriers to trade 96 technical management 145 technical manager 147 technical requirements 33 test facility 99 test item 100, 106 test methods 36

Index test report 39 test systems 106 top management 146 total quality management 113 traceability 17, 37, 63, 201, 212, 298, 299, 300, 308 traceability chain 209 training 35, 122 transportation 140 tree diagram 130 true value 10 trueness 10, 172, 217, 228, 233. 234 t-test 191 t-values 172 two-sample t-test 178 two-tailed question 169 type A evaluation (of uncertainty) 16, 255 type B evaluation (of uncertainty) 16, 256

U uncertainty 16, 34, 83, 200, 204, 212, 219, 247, 300 uncertainty estimation 257

V validation 12, 36, 62, 215, 304 validity 250 variance 166 variation 161 verification 12 VIM 2

W waiting lines 139 warning limit 278, 280 work environment 56 work instructions 48 working range 187, 219, 229

X X-chart 282

Z zero defects 132 z-score 319

331

Quality Assurance in Analytical Chemistry: Training and Teaching - Second edition

Quality Assurance in the Analytical Chemistry Laboratory

Challenges in Analytical Quality Assurance

Challenges in Analytical Quality Assurance

Quality Assurance in Dialysis, Second Edition

Quality Assurance and Quality Control in the Analytical Chemical Laboratory: A Practical Approach (Analytical Chemistry)

Quality and Reliability in Analytical Chemistry

Quality and Reliability in Analytical Chemistry

Quality Assurance in Analytical Chemistry (Analytical Techniques in the Sciences (AnTs) *)